Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B1/00—Electrolytic production of inorganic compounds or non-metals
  • C25B1/01—Products
  • C25B1/02—Hydrogen or oxygen
  • C25B1/04—Hydrogen or oxygen by electrolysis of water
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
  • C25B11/052—Electrodes comprising one or more electrocatalytic coatings on a substrate
  • C25B11/053—Electrodes comprising one or more electrocatalytic coatings on a substrate characterised by multilayer electrocatalytic coatings
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
  • C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
  • C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
  • C25B11/061—Metal or alloy
  • C25B11/063—Valve metal, e.g. titanium
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
  • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
  • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
  • C25B11/093—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds at least one noble metal or noble metal oxide and at least one non-noble metal oxide
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
  • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
  • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
  • C25B11/097—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds comprising two or more noble metals or noble metal alloys

Definitions

• Electrodes coatings relate generally to electrode coatings and, more particularly, to multi-layered electrode coatings, their method of preparation, and use.
• an electrode may include an electrically conductive substrate.
• the electrode may include a first coating on a surface of the electrically conductive substrate.
• the first coating on the surface of the electrically conductive substrate may include one or more of platinum, iridium, titanium, and tantalum.
• the electrode further may include a second coating a surface of the first coating.
• the second coating on the surface of the first coating may include one or more of tantalum, iridium, platinum, or ruthenium.
• the second coating may have a substantially uniform composition and a thickness of less than about 100 nm.
• the electrically conductive substrate may be a metal.
• the metal may be selected from the group consisting of titanium, zirconium, niobium, and tantalum, or alloys thereof. In specific embodiments, the metal may be titanium or a titanium alloy.
• the first coating may include a mixture of titanium and tantalum or any oxide thereof, e.g., a mixture of a titanium oxide and a tantalum oxide.
• the first coating may include an iridium-based mixed metal oxide.
• the first coating may include platinum or an oxide thereof.
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 tantalum.
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 titanium.
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 iridium.
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 platinum.
• the first coating has a thickness of about 100 nm to about 3000 nm.
• the second coating may include a mixture of iridium and tantalum or any oxide thereof, e.g., a mixture of an iridium oxide and a tantalum oxide.
• a molar ratio of iridium to tantalum in the second coating may be about 2: 1 to about 9: 1.
• the second coating may include about 0.1 g/m 2 to about 100 g/m 2 tantalum and about 0.1 g/m 2 to about 100 g/m 2 iridium.
• the second coating may include iridium or an oxide thereof.
• the second coating may include about 0.1 g/m 2 to about 100 g/m 2 iridium.
• the second coating may include platinum or an oxide thereof.
• the second coating may include about 0.1 g/m 2 to about 200 g/m 2 platinum.
• the second coating may have a thickness of about 10 nm to about 100 nm.
• the electrode may provide for about a 300% improvement in durability than an electrode comprising a single layer coating consisting of a composition of the second coating.
• the electrode may provide for about a 50% greater activity than an electrode comprising a single layer coating consisting of a composition of the second coating.
• a method of preparing an electrode may include applying a first coating including one or more of platinum, iridium, titanium, or tantalum to a surface of an electrically conductive substrate.
• the method may include applying a second coating comprising an oxide of one or more of tantalum, iridium, platinum, or ruthenium to a surface of the first coating.
• the applied second coating may have a substantially uniform composition and a thickness of less than about 100 nm.
• the method may include, prior to applying the first coating, preparing the electrically conductive substrate to remove contaminants and to develop the surface.
• the electrically conductive substrate may be prepared using one or more of a chemical bath, laser treatment, oxidative plasma treatment, or reductive plasma treatment.
• the first coating may be applied using physical application, chemical application, or magnetron sputtering.
• the method may include, after applying the first coating, drying the first coating.
• the second coating may be applied using atomic layer deposition, e.g., spatial atomic layer deposition (sALD).
• atomic layer deposition e.g., spatial atomic layer deposition (sALD).
• the method may include, after applying the second coating, heat treating the electrode.
• the method may include preparing an electrode.
• the prepared electrode may be any electrode disclosed herein, e.g., an electrode including an electrically conductive substrate, a first coating on a surface of the electrically conductive substrate including one or more of platinum, iridium, titanium, and tantalum and a second coating on a surface of the first coating including one or more of tantalum, iridium, platinum, or ruthenium having a substantially uniform composition and a thickness of less than about 100 nm.
• the method further may include installing the electrode in an electrolytic cell.
• an electrolytic cell may have an anode and a cathode.
• the electrolytic cell may include an electrolyte layer disposed between the anode and cathode permitting transport of protons from the anode to the cathode.
• the electrolyte layer may include a substrate sufficient for transporting protons, a first coating on a surface of the substrate including one or more of platinum, iridium, titanium, and tantalum, and a second coating on a surface of first coating including one or more of tantalum, iridium, platinum, or ruthenium.
• the second coating may have a substantially uniform composition and a thickness of less than about 100 nm.
• an electrolytic cell may have an anode that may be any electrode disclosed herein, e.g., an electrode including an electrically conductive substrate, a first coating on a surface of the electrically conductive substrate including one or more of platinum, iridium, titanium, and tantalum and a second coating on a surface of the first coating including one or more of tantalum, iridium, platinum, or ruthenium having a substantially uniform composition and a thickness of less than about 100 nm.
• the electrolytic cell may include a cathode.
• the electrolytic cell further may include an electrolyte layer disposed between the anode and cathode, the electrolyte layer permitting transport of protons from the anode to the cathode.
• an electrolyzer may include an electrolytic cell as disclosed herein, e.g., an electrolytic cell having an anode that may be any electrode disclosed herein, e.g., an electrode including an electrically conductive substrate, a first coating on a surface of the electrically conductive substrate including one or more of platinum, iridium, titanium, and tantalum and a second coating a surface of the first coating including one or more of tantalum, iridium, platinum, or ruthenium having a substantially uniform composition and a thickness of less than about 100 nm, a cathode, and an electrolyte layer disposed between the anode and cathode permitting transport of protons from the anode to the cathode.
• an electrolytic cell as disclosed herein, e.g., an electrolytic cell having an anode that may be any electrode disclosed herein, e.g., an electrode including an electrically conductive substrate, a first coating on a surface of the electrically conductive substrate including one or more of
• the electrolyzer may include an electrolytic cell as disclosed herein, e.g., an electrolytic cell having an anode, a cathode, and an electrolytic cell including an electrolyte layer disposed between the anode and cathode permitting transport of protons from the anode to the cathode including a substrate sufficient for transporting protons, a first coating on a surface of the substrate including one or more of platinum, iridium, titanium, and tantalum, and a second coating on a surface of first coating including one or more of tantalum, iridium, platinum, or ruthenium having a substantially uniform composition and a thickness of less than about 100 nm.
• an electrolytic cell as disclosed herein, e.g., an electrolytic cell having an anode, a cathode, and an electrolytic cell including an electrolyte layer disposed between the anode and cathode permitting transport of protons from the anode to the cathode including a substrate sufficient for transporting pro
• the electrolyzer further may include a power source for driving the electrolytic cell.
• FIG. l is a side view of an electrode according to one embodiment of the disclosure.
• FIG. 2 is a schematic of an electrolyzer according to one embodiment of the disclosure
• FIG. 3 illustrates the lifetime of electrode samples prepared with different surface treatments and deposition methods
• FIG. 4 illustrates the lifetime of electrode samples prepared with deposition methods
• FIG. 5 A illustrates a scanning electron microscopy (SEM) image of a vertical crosssection of an electrode having an electrodeposited second layer
• FIG. 5B illustrates a scanning electron microscopy (SEM) image of a vertical crosssection of an electrode having a second layer deposited with sALD;
• FIG. 6 illustrates the oxygen evolution reaction (OER) activity of electrodes with and without a Ti-Ta interlayer
• FIG. 7 illustrates the durability of electrodes with and without a Ti-Ta interlayer
• FIG. 8 illustrates the performance over time of electrodes with and without a Ti-Ta interlayer when used in a polymer electrolyte membrane (PEM) electrolyzer;
• PEM polymer electrolyte membrane
• FIG. 9 illustrates a focused ion beam vertical cross-section of an electrode according to this disclosure as an electron map
• FIG. 10 A- IOC illustrates SEM/energy dispersive X-ray spectroscopy (EDS) map images of the distribution of various elements in the electrode
• FIG. 11 illustrates the relative distribution of Ir and Ta in the electrode illustrated in FIGS. 9 and 10A-1C taken along the solid line illustrated in FIG. 9.
• Electrodes are a solid electric conductor through which an electric current enters or leaves an electrolytic cell or other medium. Electrodes may be used in any electrochemical process that requires an electrical conductor. For example, electrodes may be used in electrogalvanizing, electroplating, electro-tinning, electroforming, electrowinning (e.g., electrowinning of metals such as copper, nickel, and zinc), and other electrochemical processes. Electrodes may be used in any halogen-evolving processes, such as hypochlorite, chlorate, and chlor alkali production, or in chlor-organic synthesis. Electrodes may also be used in electrolytic chlorination systems and processes. Electrolytic chlorination systems and processes may produce sodium hypochlorite through the electrolysis of a brine solution.
• Electrodes may be used in electrolytic cells.
• An electrolytic cell is an electrochemical cell that may be used to overcome a positive free energy, which indicates a non-spontaneous reaction, and force a chemical reaction in a desired direction.
• the electrolytic cell converts electrical energy into chemical energy or produces chemical products through a chemical reaction.
• the electrode in an electrolytic cell may be referred to as either an anode or a cathode, depending on the direction of electrical current through the cell.
• the anode is an electrode at which electrons leave the cell and oxidation of ions within the cell occurs
• the cathode is an electrode at which electrons enter the cell and reduction of ions within the cell occurs.
• the direction of current through the cell is from the anode to the cathode.
• Each electrode may become either the anode or the cathode depending on the process and the direction of current through the cell.
• the design of electrolytic cells and their electrodes may depend on one or more factors.
• the one or more factors may include, for example, construction and operating costs, desired product, electrical, chemical, and transport properties, electrode materials, shapes and surface properties, pH of the system (for example, electrolyte pH), and temperature of the system (for example, electrolyte temperature), competing undesirable reactions, and undesirable byproducts.
• one or more properties of the process may affect the effectiveness of the system and process, for example, the service life of the electrodes. For example, exposure to one or more of a high current density, low pH, or high temperature may lower the service life of an electrode. In some embodiments, exposure to one or more of a high current density, low pH, or high temperature may cause passivation of the electrode.
• Passivation is the inhibition of a dissolution reaction caused by the formation of nondissolving films.
• a dissolution reaction is a process by which the original state of a solvent becomes a solute.
• Anode and/ or cathode passivation may result in one or more of lost production capacity, increased power costs, and decreased anode and/ or cathode quality.
• anode passivation is the growth of an insulating titanium dioxide layer in the coating and the substrate, which increases the electrical potential in the anode, and causes deactivation of the anode.
• exposure to one or more of a high current density, low pH, or high temperature may cause wear of the electrode. Wear of the electrode, or “electrode wear” is the removal of material from the electrode.
• exposure to one or more of a high current density, low pH, or high temperature may cause both passivation and wear of the electrode.
• the electrolytic cell may comprise an electrolyte.
• An electrolyte is a substance that produces an electrically conducting solution when in contact with a polar solvent, such as water. Electrolytes can be solid or liquid. When an electric potential, or voltage, is applied to the electrolyte, the cations are drawn to the electrode that has an abundance of electrons, and the anions are drawn to the electrode that has a deficit of electrons. The movement of anions and cations in opposite directions within the solution amounts to a current.
• An electrolyte may be referred to as strong or weak, depending on the dissociation of the solute. If a high proportion, for example, greater than 50%, of the solute dissociates to form free ions, the electrolyte is strong. If a high proportion, for example, less than 50%, of the solute does not dissociate, the electrolyte is weak.
• Electrolytes having a low pH may refer to electrolytes having an acidic pH, for example, less than a pH of 7.
• the electrolytes may be strong acid electrolytes.
• the strong acid electrolyte may be sulfuric acid.
• low pH may refer to electrolytes having a pH lower than about 3. In some embodiments, low pH may refer to electrolytes having a pH lower than about 2. In some embodiments, low pH may refer to electrolytes having a pH lower than about 1. In some embodiments, low pH may refer to a pH lower than about 0.8. In some embodiments, low pH may refer to a pH lower than about 0.6. In some embodiments, low pH may refer to a pH lower than about 0.4. In some embodiments, low pH may refer to a pH lower than about 0.2.
• electrodes may be exposed to electrolytes having a high temperature.
• a high temperature may be a temperature at which the cell voltage of the electrode undesirably decreases.
• a high temperature may be a temperature higher than about 50°C. In some embodiments, a high temperature is higher than about 55 °C. In some embodiments, a high temperature is higher than about 60 °C. In some embodiments, a high temperature is higher than about 65 °C. In some embodiments, a high temperature is higher than about 70 °C.
• electrodes may be exposed to high current densities. A current density is a measure of the density of an electric current.
• Electrodes have a finite, positive resistance, causing them to dissipate power in the form of heat. The current density must be kept sufficiently low to protect the electrode from passivation or wear.
• a high current density is a current density that causes at least one of passivation and wear of the electrodes.
• a high current density may be higher than about 0.5 kA/m 2 .
• a high current density may be higher than about 1.0 kA/m 2 .
• a high current density may be higher than about 1.5 kA/m 2 .
• a high current density may be higher than about 2.0 kA/m 2 .
• a high current density may be higher than about 2.5 kA/m 2 .
• a high current density may be higher than about 3.0 kA/m 2 .
• a high current density may be higher than about 3.5 kA/m 2 .
• a high current density may be higher than about 4.0 kA/m 2 .
• a high current density may be higher than about 4.5 kA/m 2 .
• a high current density may be about 5.0 kA/m 2 .
• a high current density may be up to about 15 kA/m 2 .
• PEM water electrolysis is a technology that uses an electrochemical process to split water into its constituent elements, hydrogen and oxygen. The process involves the use of a polymer electrolyte membrane (PEM) as the electrolyte material, which allows for the selective transport of protons while blocking the passage of electrons.
• PEM water electrolysis utilizes an electrolysis cell, which typically comprises two electrodes, an anode and cathode, immersed in water. The electrodes are often made of porous, conductive materials.
• the PEM is a solid polymer material that acts as an electrolyte, allowing for the transport of protons from the anode to the cathode while preventing the mixing of hydrogen and oxygen gases. Hydrogen gas is generated at the cathode, and oxygen gas is produced at the anode. The protons transported through the PEM combine with electrons at the cathode to form hydrogen gas.
• the electrolyte membrane of PEM electrolyzers is generally coated in a catalytic material. In this configuration, the catalyst coated membrane (CCM) is disposed between two porous transport layers, typically made from titanium, carbon, or another porous conductive material. To make electrical contact, the porous transport layers are forced into physical contact with the CCM.
• PEM water electrolysis is its ability to produce high-purity hydrogen gas, as the membrane selectively allows only protons to pass through, preventing gas crossover and contamination. For this reason, PEM water electrolysis is commonly used in the production of hydrogen for various applications, including fuel cells for vehicles, energy storage, and industrial processes.
• a catalyst-coated porous transport layer is a component commonly used in various electrochemical devices, including electrolyzers, combining a porous material with a catalyst to enhance the efficiency of chemical reactions occurring at the electrode interface.
• the porous transport layer is typically a thin, permeable material that facilitates the movement of reactants and products between the electrode and the surrounding environment, providing a pathway for gases and ions to reach the catalyst layer while maintaining good electrical conductivity.
• the catalyst coating is a thin layer of catalytic material applied onto the porous transport layer, which aids in accelerating specific electrochemical reactions that take place at the electrode surface.
• the catalyst-coated porous transport layer increases the effective surface area for electrochemical reactions, which helps to maximize the contact between reactants and the catalyst, improving reaction kinetics.
• the porous structure of the transport layer allows for the efficient transport of reactants (e.g., hydrogen, oxygen) and products (e.g., water) to and from the catalyst sites.
• the porous transport layer also serves as an electron conductor, facilitating the flow of electrons generated during electrochemical reactions. Furthermore, the porosity of the transport layer allows for the diffusion of gases to and from the catalyst sites.
• Mixed metal oxide coatings for dimensionally stable anodes are typically prepared through a paint-thermal decomposition route.
• the precious metal precursor typically a chloride salt precursor, and a metal precursor, e.g., Ti, Zr, Nb, or Ta
• a solvent e.g., an alcohol
• the coated sub state is heat-treated in an oven or furnace to convert the precursors into their respective oxides.
• an electrode made using the aforementioned process is a mixture of iridium chloride and tantalum ethoxide, dissolved in butanol, and applied onto a Ti substrate.
• Spatial Atomic Layer Deposition is a derivative of standard (or time- separated) Atomic Layer Deposition (ALD) and represents a cutting-edge technique in thin film deposition, offering precise control over thickness and uniformity at the nanoscale.
• metal precursors are used that are very volatile and decompose at low temperatures. The precursors are transferred via a carrier gas onto a titanium substrate, either sequentially (“supercycles”) or simultaneously (“co- dosing”). In a next step that is spatially separated from the previous step in sALD, the precursors are converted in their respective oxides.
• sALD segregates surface reactions into distinct zones rather than conducting them sequentially within a single reaction chamber.
• Film growth is achieved by exposing the substrate to the locations containing the different precursors.
• This approach enables deposition on larger surfaces and non-planar substrates while upholding advantages of traditional ALD. Eliminating the purge step that is necessary in conventional ALD, accelerates the process, making it well-suited for high-throughput methods and significantly enhances its adaptability and scalability at reduced expenses.
• one benefit of sALD is that it can operate at ambient pressures while still maintaining consistent deposition rates and has no requirement for vacuum chambers, permitting the processing to be automated.
• a “two coating electrode” refers to an electrode that is coated on at least one of its surfaces with a first coating comprising a mixture to provide the first coating, and a second coating that at least partially coats the first coating to provide a second coating. More than one application of the first coating may be performed to achieve the desired coating loading. More than one application of the second coating may be performed to achieve the desired coating mass loading. In general, the mass loadings of the coatings are based on the geometric areas the materials are being applied to, i.e., not limited to specifical surface areas of the electrode.
• the first coating may be applied directly to a surface of the electrode substrate as an interlayer, and the second coating may be applied directly to a surface of the first coating.
• the application of the coating can be fractional on the surface or can be over substantially all of the exposed surface.
• the first coating and the second coating may increase activity of the electrode.
• the first coating may reduce corrosion of the electrode.
• the second coating may reduce wear of the electrode.
• the second coating may increase catalytic activity of the electrode.
• the electrode substrate surface may be at least partially covered with a first coating comprising a mixture.
• the first coating may be at least partially covered by a second coating comprising a mixture.
• the second coating may be a mixture comprising iridium and tantalum or an oxide thereof, e.g., a mixture of an iridium oxide and a tantalum oxide.
• the second coating may be a mixture consisting essentially of iridium and tantalum or an oxide thereof, e.g., a mixture of an iridium oxide and a tantalum oxide.
• the first coating may be a mixture consisting essentially of iridium or an iridium-based mixed metal oxide (MMO).
• MMO iridium-based mixed metal oxide
• the second coating may be substantially platinum or an oxide thereof.
• the second coating includes iridium.
• the electrode substrate may be any substrate having electrically conductive properties.
• the electrode substrate may be any substrate having sufficient mechanical strength to serve as a support for the coating.
• the electrode substrate may be any substrate having a resistance to corrosion when exposed to the interior environment of an electrolytic cell.
• the electrode substrate may be a metal.
• the electrode substrate may be a valve metal or an alloy thereof.
• Valve metals are any of the transition metals of Group IV and V of the periodic table, including titanium, vanadium, zirconium, niobium, hafnium, and tantalum.
• suitable valve metals include titanium, zirconium, niobium, and tantalum.
• the electrode substrate preferably comprises titanium. Titanium may be preferred because of its availability, chemical properties, and low cost.
• the first coating may comprise a mixture of titanium and tantalum or an oxide thereof, e.g., a mixture of a titanium oxide and a tantalum oxide.
• the first coating may consist essentially of titanium and tantalum or an oxide thereof, e.g., a mixture of a titanium oxide and a tantalum oxide.
• the first coating may consist of a mixture of titanium and tantalum or an oxide thereof, e.g., a mixture of a titanium oxide and a tantalum oxide.
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 tantalum.
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 tantalum, e.g., about 1 g/m 2 to about 10 g/m 2 tantalum, about 5 g/m 2 to about 15 g/m 2 tantalum, about 10 g/m 2 to about 20 g/m 2 tantalum, about 15 g/m 2 to about 25 g/m 2 tantalum, about 20 g/m 2 to about 30 g/m 2 tantalum, about 25 g/m 2 to about 35 g/m 2 tantalum, about 30 g/m 2 to about 40 g/m 2 tantalum, about 35 g/m 2 to about 45 g/m 2 tantalum, about 40 g/m 2 to about 50 g/m 2 tantalum, about 45 g/m 2 to about 55 g/m 2 tantalum, about 50 g/m 2 to about 60 g/m 2 tantalum, about 55 g/m 2 to about 65 g
• the first coating may include about 0.1 g/m 2 of tantalum, about 0.2 g/m 2 of tantalum, about 0.3 g/m 2 of tantalum, about 0.4 g/m 2 of tantalum, about 0.5 g/m 2 of tantalum, about 0.6 g/m 2 of tantalum, about 0.7 g/m 2 of tantalum, about 0.8 g/m 2 of tantalum, about 0.9 g/m 2 of tantalum, about 1 g/m 2 of tantalum, about 2 g/m 2 of tantalum, about 3 g/m 2 of tantalum, about 4 g/m 2 of tantalum, about 5 g/m 2 of tantalum, about 6 g/m 2 of tantalum, about 7 g/m 2 of tantalum, about 8 g/m 2 of tantalum, about 9 g/m 2 of tantalum, about 10 g/m 2 of tantalum, about 11 g/m 2 of
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 titanium, e.g., about 1 g/m 2 to about 10 g/m 2 titanium, about 5 g/m 2 to about 15 g/m 2 titanium, about 10 g/m 2 to about 20 g/m 2 titanium, about 15 g/m 2 to about 25 g/m 2 titanium, about 20 g/m 2 to about 30 g/m 2 titanium, about 25 g/m 2 to about 35 g/m 2 titanium, about 30 g/m 2 to about 40 g/m 2 titanium, about 35 g/m 2 to about 45 g/m 2 titanium, about 40 g/m 2 to about 50 g/m 2 titanium, about 45 g/m 2 to about 55 g/m 2 titanium, about 50 g/m 2 to about 60 g/m 2 titanium, about 55 g/m 2 to about 65 g/m 2 titanium, about 60 g/m 2 to about 70 g/m 2 titanium, about 65 g
• the first coating may include about 0.1 g/m 2 of titanium, about 0.2 g/m 2 of titanium, about 0.3 g/m 2 of titanium, about 0.4 g/m 2 of titanium, about 0.5 g/m 2 of titanium, about 0.6 g/m 2 of titanium, about 0.7 g/m 2 of titanium, about 0.8 g/m 2 of titanium, about 0.9 g/m 2 of titanium, about 1 g/m 2 of titanium, about 2 g/m 2 of titanium, about 3 g/m 2 of titanium, about 4 g/m 2 of titanium, about 5 g/m 2 of titanium, about 6 g/m 2 of titanium, about 7 g/m 2 of titanium, about 8 g/m 2 of titanium, about 9 g/m 2 of titanium, about 10 g/m 2 of titanium, about 11 g/m 2 of titanium, about 12 g/m 2 of titanium, about 13 g/m 2 of titanium, about 14 g/m 2 of titanium, about 15 g/m
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 iridium, e.g., about 1 g/m 2 to about 10 g/m 2 iridium, about 5 g/m 2 to about 15 g/m 2 iridium, about 10 g/m 2 to about 20 g/m 2 iridium, about 15 g/m 2 to about 25 g/m 2 iridium, about 20 g/m 2 to about 30 g/m 2 iridium, about 25 g/m 2 to about 35 g/m 2 iridium, about 30 g/m 2 to about 40 g/m 2 iridium, about 35 g/m 2 to about 45 g/m 2 iridium, about 40 g/m 2 to about 50 g/m 2 iridium, about 45 g/m 2 to about 55 g/m 2 iridium, about 50 g/m 2 to about 60 g/m 2 iridium, about 55
• the first coating may include about 0.1 g/m 2 of iridium, about 0.2 g/m 2 of iridium, about 0.3 g/m 2 of iridium, about 0.4 g/m 2 of iridium, about 0.5 g/m 2 of iridium, about 0.6 g/m 2 of iridium, about 0.7 g/m 2 of iridium, about 0.8 g/m 2 of iridium, about 0.9 g/m 2 of iridium, about 1 g/m 2 of iridium, about 2 g/m 2 of iridium, about 3 g/m 2 of iridium, about 4 g/m 2 of iridium, about 5 g/m 2 of iridium, about 6 g/m 2 of iridium, about 7 g/m 2 of iridium, about 8 g/m 2 of iridium, about 9 g/m 2 of iridium, about 10
• the first coating may include about 0.1 g/m 2 to about 100 g/m 2 platinum, e.g., about 1 g/m 2 to about 10 g/m 2 platinum, about 5 g/m 2 to about 15 g/m 2 platinum, about 10 g/m 2 to about 20 g/m 2 platinum, about 15 g/m 2 to about 25 g/m 2 platinum, about 20 g/m 2 to about 30 g/m 2 platinum, about 25 g/m 2 to about 35 g/m 2 platinum, about 30 g/m 2 to about 40 g/m 2 platinum, about 35 g/m 2 to about 45 g/m 2 platinum, about 40 g/m 2 to about 50 g/m 2 platinum, about 45 g/m 2 to about 55 g/m 2 platinum, about 50 g/m 2 to about 60 g/m 2 platinum, about 55 g/m 2 to about 65 g/m 2 platinum, about 60 g/m 2 to about 70 g/m 2 platinum, about 65 g
• the first coating may include about 0.1 g/m 2 of platinum, about 0.2 g/m 2 of platinum, about 0.3 g/m 2 of platinum, about 0.4 g/m 2 of platinum, about 0.5 g/m 2 of platinum, about 0.6 g/m 2 of platinum, about 0.7 g/m 2 of platinum, about 0.8 g/m 2 of platinum, about 0.9 g/m 2 of platinum, about 1 g/m 2 of platinum, about 2 g/m 2 of platinum, about 3 g/m 2 of platinum, about 4 g/m 2 of platinum, about 5 g/m 2 of platinum, about 6 g/m 2 of platinum, about 7 g/m 2 of platinum, about 8 g/m 2 of platinum, about 9 g/m 2 of platinum, about 10 g/m 2 of platinum, about 11 g/m 2 of platinum, about 12 g/m 2 of platinum, about 13 g/m 2 of platinum, about 14 g/m 2 of platinum, about 15 g/m
• the first coating has a thickness of about 100 nm to about 2000 nm, e.g., about 100 nm to about 250 nm, about 200 nm to about 350 nm, about 300 nm to about 450 nm, about 400 nm to about 550 nm, about 500 nm to about 650 nm, about 600 nm to about 750 nm, about 700 nm to about 850 nm, about 800 nm to about 950 nm, about 1000 nm to about 1150 nm, about 1100 nm to about 1250 nm, about 1200 nm to about 1350 nm, about 1300 nm to about 1450 nm, about 1400 nm to about 1550 nm, about 1500 nm to about 1650 nm, about 1600 nm to about 1750 nm, about 1700 nm to about 1850 nm, or about 1800 nm to about 200 nm.
• the first layer has a thickness of about 100 nm, about 150 nm, about 200 nm, about 250 nm, about 300 nm, about 350 nm, about 400 nm, about 450 nm, about 500 nm, about 550 nm, about 600 nm, about 650 nm, about 700 nm, about 750 nm, about 800 nm, about 850 nm, about 900 nm, about 950 nm, about 1000 nm, about 1050 nm, about 1100 nm, about 1150 nm, about 1200 nm, about 1250 nm, about 1300 nm, about 1350 nm, about 1400 nm, about 1450 nm, about 1500 nm, about 1550 nm, about 1600 nm, about 1650 nm, about 1700 nm, about 1750 nm, about 1800 nm, about 1850 nm, about 1900 nm
• the thickness of the first coating may be independent of the dimensions of the electrode.
• the second coating may be substantially iridium.
• the second coating may comprise a mixture of iridium and tantalum.
• the second coating may consist essentially of a mixture of iridium and tantalum.
• the second coating may consist of iridium and tantalum.
• Iridium may be in any weight concentration or molar ration such that a desired property is achieved.
• the weight concentration of iridium is the weight of iridium compared to the weight of another component in the same layer. In some embodiments, the weight concentration of iridium is within a range of 40 wt. % to 75 wt. %.
• the weight concentration of iridium is about 65 wt. %.
• the molar ratio of iridium to tantalum in the second coating is about 2: 1 to about 9: 1.
• the molar ratio of iridium to tantalum in the second coating is about 2: 1, about 2.5: 1, about 3:1, about 3.5: 1, about 4: 1, about 4.5: 1, about 5: 1, about 5.5: 1, about 6: 1, about 6.5: 1, about 7: 1, about 7.5: 1, about 8:1, about 8.5:1, or about 9: 1.
• the second coating may be substantially platinum.
• platinum as a second coating may be deposited using any method disclosed herein, e.g., sALD and/or electrodeposition. Platinum may be in any weight concentration or molar ration such that a desired property is achieved.
• the weight concentration of platinum is the weight of platinum compared to the weight of another component in the same layer. In some embodiments, the weight concentration of platinum is within a range of 40 wt. % to 75 wt. %. In some aspects, the weight concentration of platinum is about 65 wt. %.
• the second coating may include about 0.1 g/m 2 to about 100 g/m 2 tantalum.
• the second coating may include about 1 g/m 2 to about 100 g/m 2 tantalum, e.g., about 1 g/m 2 to about 10 g/m 2 tantalum, about 5 g/m 2 to about 15 g/m 2 tantalum, about 10 g/m 2 to about 20 g/m 2 tantalum, about 15 g/m 2 to about 25 g/m 2 tantalum, about 20 g/m 2 to about 30 g/m 2 tantalum, about 25 g/m 2 to about 35 g/m 2 tantalum, about 30 g/m 2 to about 40 g/m 2 tantalum, about 35 g/m 2 to about 45 g/m 2 tantalum, about 40 g/m 2 to about 50 g/m 2 tantalum, about 45 g/m 2 to about 55 g/m 2 tantalum, about 50 g/m 2
• the second coating may include about 0.1 g/m 2 of tantalum, about 0.2 g/m 2 of tantalum, about 0.3 g/m 2 of tantalum, about 0.4 g/m 2 of tantalum, about 0.5 g/m 2 of tantalum, about 0.6 g/m 2 of tantalum, about 0.7 g/m 2 of tantalum, about 0.8 g/m 2 of tantalum, about 0.9 g/m 2 of tantalum, about 1 g/m 2 of tantalum, about 2 g/m 2 of tantalum, about 3 g/m 2 of tantalum, about 4 g/m 2 of tantalum, about 5 g/m 2 of tantalum, about 6 g/m 2 of tantalum, about 7 g/m 2 of tantalum, about 8 g/m 2 of tantalum, about 9 g/m 2 of tantalum, about 10 g/m 2 of tantalum, about 11 g/m 2 of
• the second coating may include about 0.1 g/m 2 to about 100 g/m 2 ruthenium, e.g., about 1 g/m 2 to about 10 g/m 2 ruthenium, about 5 g/m 2 to about 15 g/m 2 ruthenium, about 10 g/m 2 to about 20 g/m 2 ruthenium, about 15 g/m 2 to about 25 g/m 2 ruthenium, about 20 g/m 2 to about 30 g/m 2 ruthenium, about 25 g/m 2 to about 35 g/m 2 ruthenium, about 30 g/m 2 to about 40 g/m 2 ruthenium, about 35 g/m 2 to about 45 g/m 2 ruthenium, about 40 g/m 2 to about 50 g/m 2 ruthenium, about 45 g/m 2 to about 55 g/m 2 ruthenium, about 50 g/m 2 to about 60 g/m 2 ruthenium, about 55
• the second coating may include about 0.1 g/m 2 of ruthenium, about 0.2 g/m 2 of ruthenium, about 0.3 g/m 2 of ruthenium, about 0.4 g/m 2 of ruthenium, about 0.5 g/m 2 of ruthenium, about 0.6 g/m 2 of ruthenium, about 0.7 g/m 2 of ruthenium, about 0.8 g/m 2 of ruthenium, about 0.9 g/m 2 of ruthenium, about 1 g/m 2 of ruthenium, about 2 g/m 2 of ruthenium, about 3 g/m 2 of ruthenium, about 4 g/m 2 of ruthenium, about 5 g/m 2 of ruthenium, about 6 g/m 2 of ruthenium, about 7 g/m 2 of ruthenium, about 8 g/m 2 of ruthenium, about 9 g/m 2 of ruthenium, about 10
• the second coating may include about 0.1 g/m 2 to about 100 g/m 2 iridium, e.g., about 1 g/m 2 to about 10 g/m 2 iridium, about 5 g/m 2 to about 15 g/m 2 iridium, about 10 g/m 2 to about 20 g/m 2 iridium, about 15 g/m 2 to about 25 g/m 2 iridium, about 20 g/m 2 to about 30 g/m 2 iridium, about 25 g/m 2 to about 35 g/m 2 iridium, about 30 g/m 2 to about 40 g/m 2 iridium, about 35 g/m 2 to about 45 g/m 2 iridium, about 40 g/m 2 to about 50 g/m 2 iridium, about 45 g/m 2 to about 55 g/m 2 iridium, about 50 g/m 2 to about 60 g/m 2 iridium, about 55
• the second coating may include about 0.1 g/m 2 of iridium, about 0.2 g/m 2 of iridium, about 0.3 g/m 2 of iridium, about 0.4 g/m 2 of iridium, about 0.5 g/m 2 of iridium, about 0.6 g/m 2 of iridium, about 0.7 g/m 2 of iridium, about 0.8 g/m 2 of iridium, about 0.9 g/m 2 of iridium, about 1 g/m 2 of iridium, about 2 g/m 2 of iridium, about 3 g/m 2 of iridium, about 4 g/m 2 of iridium, about 5 g/m 2 of iridium, about 6 g/m 2 of iridium, about 7 g/m 2 of iridium, about 8 g/m 2 of iridium, about 9 g/m 2 of iridium, about 10
• the second coating may include about 0.1 g/m 2 to about 200 g/m 2 platinum, e.g., about 1 g/m 2 to about 10 g/m 2 platinum, about 5 g/m 2 to about 15 g/m 2 platinum, about 10 g/m 2 to about 20 g/m 2 platinum, about 15 g/m 2 to about 25 g/m 2 platinum, about 20 g/m 2 to about 30 g/m 2 platinum, about 25 g/m 2 to about 35 g/m 2 platinum, about 30 g/m 2 to about 40 g/m 2 platinum, about 35 g/m 2 to about 45 g/m 2 platinum, about 40 g/m 2 to about 50 g/m 2 platinum, about 45 g/m 2 to about 55 g/m 2 platinum, about 50 g/m 2 to about 60 g/m 2 platinum, about 55 g/m 2 to about 65 g/m 2 platinum, about 60 g/m 2 to about 70 g/m 2 platinum, about 65 g
• the second coating may include about 0.1 g/m 2 of platinum, about 0.2 g/m 2 of platinum, about 0.3 g/m 2 of platinum, about 0.4 g/m 2 of platinum, about 0.5 g/m 2 of platinum, about 0.6 g/m 2 of platinum, about 0.7 g/m 2 of platinum, about 0.8 g/m 2 of platinum, about 0.9 g/m 2 of platinum, about 1 g/m 2 of platinum, about 2 g/m 2 of platinum, about 3 g/m 2 of platinum, about 4 g/m 2 of platinum, about 5 g/m 2 of platinum, about 6 g/m 2 of platinum, about 7 g/m 2 of platinum, about 8 g/m 2 of platinum, about 9 g/m 2 of platinum, about 10 g/m 2 of platinum, about 11 g/m 2 of platinum, about 12 g/m 2 of platinum, about 13 g/m 2 of platinum, about 14 g/m 2 of platinum, about 15 g/m
• the second coating as a thickness of about 10 nm to about 100 nm, e.g., about 10 nm to about 20 nm, about 15 nm to about 25 nm, about 20 nm to about 30 nm, about 25 nm to about 35 nm, about 30 nm to about 40 nm, about 35 nm to about 45 nm, about 40 nm to about 50 nm, about 45 nm to about 55 nm, about 50 nm to about 60 nm, about 55 nm to about 65 nm, about 60 nm to about 70 nm, about 65 nm to about 75 nm, about 70 nm to about 80 nm, about 75 nm to about 85 nm, about 80 nm to about 90 nm, about 85 nm to about 95 nm, or about 90 nm to about 100 nm.
• the second coating has a thickness of , about 10 nm, about 11 nm, about 12 nm, about 13 nm, about 14 nm, about 15 nm, about 16 nm, about 17 nm, about 18 nm, about 19 nm, about 20 nm, about 21 nm, about 22 nm, about 23 nm, about 24 nm, about 25 nm, about 26 nm, about 27 nm, about 28 nm, about 29 nm, about 30 nm, about 31 nm, about 32 nm, about 33 nm, about 34 nm, about 35 nm, about 36 nm, about 37 nm, about 38 nm, about 39 nm, about 40 nm, about 41 nm, about 42 nm, about 43 nm, about 44 nm, about 45 nm, about 46 nm, about 47 nm, about 48 nm, about 49 nm,
• the thickness of the second coating may be independent of the dimensions of the electrode.
• the combination of chemical elements, coating thickness, and coating uniformity may provide for improvements in one or more properties of the electrodes, e.g., catalytic activity, durability, and the like.
• electrodes of this disclosure can provide for about a 300% improvement in durability than an electrode comprising a single layer coating consisting of a composition of the second coating.
• the durability of an electrode may be assessed by performance of the electrode with and without a deposited interlayer under galvanostatic conditions. The time necessary for an electrode to reach a certain potential on the working electrode provides an indication of the lifetime of the electrode.
• an electrode having both a first coating and a second coating generally is more durable than an electrode with a single coating.
• electrodes of this disclosure provide for about a 50% greater activity, e.g., catalytic activity, e.g., oxygen evolution reaction activity, than an electrode comprising a single layer coating consisting of a composition of the second coating.
• the behavior of an electrode as determined by a current-voltage diagram, i.e., an I-V curve can be used to determine if an electrode coating has an effect on an electrochemical reaction.
• an electrode is considered to be more active if and I-V curve has a steeper slope, i.e., greater current at a lower voltage in the electrochemical cell.
• an electrode having both a first coating and a second coating generally exhibits an increased activity for one or more electrochemical reactions than an electrode with a single coating as determined by the steepness of the curve as a voltage is swept.
• the electrode substrate may be applied with, for example, coated with the first and second coatings according to any application process, e.g., physical application, chemical application, or magnetron sputtering, that may provide for a homogeneous or substantially homogeneous dispersal of material to the desired surface.
• the first and second coatings may be applied to the electrode substrate by brushing, rolling, dipping, spraying, or by atomic or molecular layer deposition, or the like.
• the electrode substrate may be coated with the first and second coating mixtures according to a thermal decomposition method.
• the first coating to second coating may be applied by dissolving the metal precursor in a solvent, applying the dissolved precursor to the substrate, and evaporating the solvent.
• the electrode substrate may be coated with the first and second coating mixtures according to an atomic layer deposition process.
• one or both of the first coating and second coating may be applied using sALD.
• the electrode substrate may first be prepared for application of a coating.
• the electrode substrate may be treated or cleaned to accept the coating, or to provide for a surface that may be susceptible to adherence of a coating.
• Cleaning of the electrode substrate may be performed by a laser treatment, chemical baths, e.g., chemical degreasing, electrolytic degreasing, or treatment with an oxidizing acid.
• Chemical degreasing may be performed using a polar solvent, such as acetone, acetonitrile, dimethylformamide (DMF), dimelthylsulfoxide (DMSO), isopropanol, and methanol.
• Suitable acids used to treat electrode surfaces include haloacids such as HC1 and organic acids such as oxalic acid.
• the electrode substrate may be pretreated using one or more plasma treatments.
• an electrode substrate may first be treated with an oxidative plasma to remove impurities from the surface followed by a reducing plasma to remove any residual oxides from the surface.
• the electrode substrate may be prepared by any method suitable to remove or minimize contaminants and develop high surface roughness that may hinder proper adhesion of the coating to the surface of the substrate and lower the effective current density for coated metal surfaces, thus also decreasing the electrode operating potential. Longer lived anodes translate into less down time and cell maintenance, thereby cutting operating cost.
• the electrode substrate may be prepared by a cleaning, sandblasting, etching, and/or pre-oxidation process.
• Electrode substrate may include plasma spraying, melt spraying with ceramic oxide particles, melt spraying of a valve metal layer onto the electrode substrate, grit blasting with a sharp grit, and annealing. Cleaning of the electrode substrate may be followed by mechanical or chemical roughening to prepare the surface for coating. In some embodiments, when the cleaning is performed via sandblasting, it may be followed by an etching process.
• a method of preparing an electrode includes applying a first coating comprising one or more of platinum, iridium, titanium, or tantalum to a surface of an electrically conductive substrate.
• the method includes applying a second coating comprising one or more of tantalum, iridium, platinum, or ruthenium to a surface of the first coating.
• the second coating has a substantially uniform composition and a thickness of less than about 100 nm.
• the method includes, prior to applying the first coating layer, preparing the electrically conductive substrate to remove contaminants and to develop the surface, e.g., using one or more of a chemical bath, laser treatment, oxidative plasma treatment, or reductive plasma treatment.
• the first coating layer is applied using physical application, chemical application, or magnetron sputtering. Following application of the first coating layer, the method includes drying the first coating layer, e.g., to remove any residual solvent.
• the electrically conductive substrate with the first coating is heated, e.g., using an oven, furnace, or other controllable heat source, or plasma treated, e.g., using a nitrogen and/or oxygen plasma, to form oxides of the metals of the first coating.
• the second coating is applied to the heat-treated first coating using any suitable deposition technique disclosed herein.
• the second coating can be applied using atomic layer deposition, e.g., sALD, e.g., in one or more passes, until an expected or desired loading of metal is achieved.
• the electrode may be heat treated, e.g., using an oven, furnace, or other controllable heat source, or plasma treated, e.g., using a nitrogen and/or oxygen plasma, to form oxides of the metals of the second coating.
• the electrode may be installed in an electrolytic cell.
• the electrolytic cell also has a power source for supplying a current to the electrodes of the electrolytic cell.
• the source of current may be a direct current source. In the current direction, one electrode typically acts as the anode and its counterpart typically acts as the cathode.
• a method of manufacturing an electrolytic cell includes preparing an electrode, e.g., as disclosed herein.
• the electrode includes an electrically conductive substrate, a first coating on a surface of the electrically conductive substrate, and a second coating on a surface of first coating.
• the first coating includes one or more of platinum, iridium, titanium, and tantalum.
• the second coating includes one or more of tantalum, iridium, platinum, or ruthenium.
• the second coating has a substantially uniform composition and a thickness of less than about 100 nm.
• the method includes installing the electrode in an electrolytic cell.
• an electrolytic cell in accordance with an aspect, there is provided an electrolytic cell.
• the electrolytic cell includes an anode and a cathode.
• the electrolytic cell further includes an electrolyte layer disposed between the anode and cathode permitting transport of protons from the anode to the cathode.
• the electrolyte layer includes a substrate sufficient for transporting protons, a first coating on a surface of the substrate and a second coating on a surface of first coating.
• the first coating includes one or more of platinum, iridium, titanium, and tantalum.
• the second coating includes one or more of tantalum, iridium, platinum, or ruthenium.
• the second coating has a substantially uniform composition and a thickness of less than about 100 nm.
• an electrolytic cell includes an anode, e.g., as disclosed herein.
• the electrode includes an electrically conductive substrate, a first coating on a surface of the electrically conductive substrate, and a second coating on a surface of first coating.
• the first coating includes one or more of platinum, iridium, titanium, and tantalum.
• the second coating includes one or more of tantalum, iridium, platinum, or ruthenium.
• the second coating has a substantially uniform composition and a thickness of less than about 100 nm.
• the electrolytic cell includes a cathode.
• the electrolytic cell further includes an electrolyte layer disposed between the anode and cathode that permits transport of protons from the anode to the cathode, e.g., when the electrolytic cell is electrically driven.
• the electrolytic cell may be part of a system and include a power source that is disposed to drive the electrolytic cell.
• the electrolytic cell may be used in a wastewater treatment system.
• the electrolytic cell may be used in a municipal or industrial wastewater treatment system.
• the electrolytic cell may be used in a chemical processing system.
• the electrolytic cell may be used in an industrial process water system.
• the electrolytic cell may be used in an electrolytic chlorine generation system.
• the system may comprise a source of salt water.
• the system may comprise a source of ballast water.
• the system may further comprise a water outlet.
• the system may comprise a potable water outlet.
• the system may further comprise a water storage unit fluidly connected to the water outlet.
• the system may further comprise a contaminant outlet.
• the system may comprise a chlorine solution outlet.
• the system may chlorine solution outlet may comprise a sodium hypochlorite solution outlet.
• the system may comprise a contaminant storage unit fluidly connected to the contaminant outlet.
• Electrode 100 comprises an electrically conductive substrate 101 and may be any substrate having electrically conductive properties.
• Substrate 101 may be a metal.
• substrate 101 may be a valve metal.
• substrate 101 may comprise titanium, vanadium, zirconium, niobium, hafnium, or tantalum.
• substrate 101 is titanium.
• substrate 101 is a membrane material, such as a fluororpolymer, e.g., a sulfonated fluoropolymer, perfluorosulfonic acid (PF SA) ionomers, or related substrates that can conduct charged species.
• PF SA perfluorosulfonic acid
• substrate 101 When a membrane is used as substrate 101, the coated membrane is used as a catalytic membrane for polymer electrolyte membrane (PEM) hydrolysis.
• PEM polymer electrolyte membrane
• Substrate 101 may be prepared for application of a coating. For example, substrate 101 may be treated or cleaned to accept the coating, or to provide for a surface that may be susceptible to adherence of a coating. Cleaning of substrate 101 may be performed by chemical degreasing, electrolytic degreasing, or treatment with an oxidizing acid. Substrate 101 may be prepared by any method suitable to remove or minimize contaminants and develop high surface roughness that may hinder proper adhesion of a coating to the surface of substrate 101 and lower the effective current density for coated metal surfaces, thus also decreasing the electrode operating potential.
• substrate 101 may be prepared by a cleaning, sandblasting, etching, and/or pre-oxidation process.
• Other methods of preparing substrate 101 may include plasma spraying, melt spraying with ceramic oxide particles, melt spraying of a valve metal layer onto the electrode substrate, grit blasting with a sharp grit, and annealing.
• Cleaning of substrate 101 may be followed by mechanical roughening to prepare the surface for coating.
• the cleaning when the cleaning is performed via sandblasting, it may be followed by an etching process.
• Substrate 101 may be coated with a first coating 102.
• First coating 102 may cover at least a portion of the surface of substrate 101.
• First coating 102 may comprise an oxide of one or more of platinum, iridium, titanium, and tantalum.
• First coating 102 may comprise one or more of platinum, iridium, titanium, and tantalum in any weight concentration such that a desired property is achieved.
• First coating 102 may be applied to the surface of substrate 101 by any known application process.
• first coating 102 may be applied to the surface of substrate 101 by brushing, rolling, or spraying.
• First coating 102 may be applied to the surface of substrate 101 using a physio-chemical application process with a dissolved precursor in a solvent or magnetron sputtering.
• First coating 102 may be coated with a second coating 103.
• Second coating 103 may cover at least a portion of first coating 102.
• Second coating 103 may comprise one or more of tantalum, iridium, platinum, or ruthenium.
• Second coating 103 may comprise one or more of tantalum, iridium, platinum, or ruthenium in any weight concentration such that a desired property is achieved, for example, increased catalytic activity.
• Second coating 103 may be applied to first coating 102 by atomic layer deposition, e.g., sALD, physical application, chemical application, i.e., a physio-chemical application process with a dissolved precursor in a solvent, or magnetron sputtering. Once applied, the second coating has a substantially uniform composition and a thickness of less than about 100 nm, e.g., as disclosed herein.
• System 200 may comprise electrolytic cell 210.
• Electrolytic cell 210 may comprise at least one electrode 100 as described herein. Electrode 100 may be at least one of an anode and a cathode. In some embodiments, electrode 100 is an anode. In some embodiments, electrolytic cell 210 includes an electrode 100 where the substrate 101 is a membrane, i.e., a catalyst coated membrane (CCM), rather than a metallic electrode substrate.
• System 200 may further comprise power source 230 operably connected to electrolytic cell 210. Power source 230 may supply direct current to electrolytic cell 210.
• One or more sensors 240 may be located within electrolytic cell 210. Sensor 240 may be configured to measure a quality parameter of system 200. In some embodiments, sensor 240 may be configured to measure one or more of the pH of the system (for example, pH of an electrolyte), the temperature of the system (for example, temperature of the electrolyte), conductivity of the electrolyte, and the current of the system. The sensors 240 may communicate, electrically or otherwise, with controller 250 to provide the controller with a signal indicative of the measured property of the system. Controller 250 may control one or more properties of the system. For example, controller 250 may control the amperage into the system from power source 230.
• the Ir precursor was Ethylcyclopentadienyl cyclohexadiene Ir ((EtCp)Ir(CHD))
• the surfaces of the samples were exposed to an N2/O2 plasma.
• a sheet of Grade 1 Ti was annealed, etched in hydrochloric acid, and subsequently rinsed.
• a butanol-based paint containing ⁇ IrCk and Ta2(OC2Hs)io was applied onto the Ti sheet in layers of 1 g/m 2 of Ir using spin coating.
• the butanol was evaporated and the dried paint coated sheet was placed into an electric furnace at 500 °C for 1 hour to convert the Ir and Ta into their respective oxides, i.e., IrCE and Ta2Os.
• three layers of the precursor paint were applied, resulting in an IrCh/Ta? ⁇ ; MMO coating with a total Ir loading of 1.59 g/m 2 .
• a homogeneous coating was obtained.
• the lifetime of the resulting Ir MMO coating was subsequently tested in 25% H2SO4 at 20,000 A/m 2 and 50 °C. A lifetime of 0.86 MAh/m 2 was obtained.
• a sheet of Grade 1 Ti was degreased with isopropanol and placed in the sALD device.
• the pretreatment of the Ti sheet consisted of both an HC1 etching and an oxidative plasma treatment to remove any impurities from the surface followed by a reducing plasma to prepare an oxide-free Ti interface.
• an N2/O2 plasma was applied to the deposited coating to convert the metal precursors to IrCE and Ta2Os onto the Ti sheet surface.
• the metal vapor dosing and plasma steps were repeated to obtain a surface loading of 1.43 g/m 2 Ir. A homogeneous coating was obtained.
• the lifetime of the resulting Ir MMO coating was subsequently tested in 25% H2SO4 at 20,000 A/m 2 and 50 °C. A lifetime of 0.95 MAh/m 2 was obtained with heat treatment after sALD deposition.
• a Grade 1 porous Ti fiber felt was annealed, etched in hydrochloric acid, and subsequently rinsed.
• a butanol-based paint containing FEIrCL and Ta2(OC2Hs)io was applied onto the Ti sheet in layers of 1 g/m 2 of Ir using spin coating. After each layer, the butanol was evaporated and the dried paint coated sheet was placed into an electric furnace at 500 °C for 1 hour to convert the Ir and Ta into their respective oxides, i.e., IrCE and Ta2Os.
• three layers of the precursor paint were applied, resulting in an IrO2/Ta2Os MMO coating. A homogeneous coating was obtained.
• the lifetime of the resulting Ir MMO coating was subsequently tested in 25% H2SO4 at 20,000 A/m 2 and 50 °C. A lifetime, expressed as MAh/m 2 , was obtained.
• a sheet of Grade 1 Ti was degreased with isopropanol and placed in the sALD device.
• the pretreatment of the Ti sheet consisted of a HC1 etch to prepare an oxide-free Ti interface.
• the dosing and heating steps were repeated to obtain a surface loading of 1 g/m 2 Ta.
• the sample was heat treated at 500 C for 25 minutes to convert the metal precursors to IrCE and Ta2Os onto the Ti sheet surface.
• the dissolved metal application and heating steps were repeated to obtain a surface loading of 3.85 g/m 2 Ir.
• a homogeneous coating was obtained.
• the lifetime of the resulting Ir MMO coating was tested in 25% H2SO4 at 20,000 A/m 2 and 50 °C and a lifetime of 10.9 MAh/m 2 was obtained.
• a second sample with only the applied Ir-Ta coating by butanol deposition was prepared as described above. This sample did not contain the Ta interlayer applied using sALD. Following application of the Ir and Ta precursors, the sample was heat treated at 500 C for 25 minutes to convert the metal precursors to EO2 and Ta2Os onto the Ti sheet surface. The dissolved metal application and heating steps were repeated to obtain a surface loading of 3.2 g/m 2 Ir. A homogeneous coating was obtained. The lifetime of the resulting Ir MMO coating was tested in 25% H2SO4 at 20,000 A/m 2 and 50 °C and a lifetime of 1.45 MAh/m 2 was obtained.
• a sheet of Grade 1 Ti was degreased with isopropanol and placed in the sALD device.
• the pretreatment of the Ti sheet consisted of an oxidative plasma treatment to remove any impurities from the surface followed by a reducing plasma to prepare an oxide-free Ti interface.
• an N2/O2 plasma was applied to the deposited coating to convert the metal precursors to RuCE and Ta2Os onto the Ti sheet surface.
• the metal vapor dosing and plasma steps were repeated to obtain a surface loading of 3 g/m 2 Ru. A homogeneous coating was obtained.
• a sheet of Grade 1 Ti was degreased with isopropanol and placed in the sALD device.
• the pretreatment of the Ti sheet consisted of an oxidative plasma treatment to remove any impurities from the surface followed by a reducing plasma to prepare an oxide-free Ti interface.
• a gradient was applied along the coating thickness, starting with only IrOx for the first coating cycles, and ending with IrOx/Ta2Os in an Ir:Ta ratio of 65:35.
• N2/O2 plasma was applied to the deposited coating to convert the metal precursors to IrCL and Ta2Os onto the Ti sheet surface.
• the metal vapor dosing and plasma steps were repeated to obtain a surface loading of 3.04 g/m 2 Ir. A homogeneous coating was obtained. No post-deposition heat treatment was performed on this sample.
• the lifetime of the resulting Ir MMO coating was subsequently tested in 25% H2SO4 at 20,000 A/m 2 and 50 °C. The lifetime was measured to be 0 MAh/m 2 .
• the Ir loading on the sample was 2.84 g/m 2 .
• the lifetime of the resulting Ir MMO coating was measured to be 0.28 MAh/m 2 .
• a Grade 1 Ti sheet was first treated with 6M hydrochloric acid (HC1) at 90°C for 90 minutes to both roughen and clean the Ti surface.
• HC1 hydrochloric acid
• Pt vapor was dosed onto the Ti sheet using sALD to form a layer of Pt on the Ti sheet.
• another Ti sheet was prepared using the same HC1 etching and Pt coating using electrodeposition.
• separate Ti sheets were etched using oxalic acid, typically considered state of the art for electrodeposited Pt coatings.
• the sALD Pt coating (0.107 MAh/g) exhibited twice the electrochemical performance compared to the conventional electrodeposited Pt coating with the same HC1 etch pretreatment (0.048 MAh/g).
• the sALD Pt coating (0.107 MAh/g) displayed about 40% improved electrochemical performance compared to the electrodeposited Pt coating with oxalic acid pretreatment (0.064 MAh/g).
• the electrochemical performance of the sALD Pt coating was compared to Ti sheets that included the deposition of various interlayers. As disclosed herein, interlayers are typically applied to protect the substrate from corrosion and increase the lifetime of the electrode.
• FIG. 1 interlayers are typically applied to protect the substrate from corrosion and increase the lifetime of the electrode.
• FIGS. 5A and 5B illustrate SEM images of vertical cross-sections of the Pt coatings on a conventional anode with a Pt/Ir interlayer with electrodeposited Pt on top (FIG. 5 A) and a sALD Pt coating (FIG. 5B).
• FIG. 5A severe defects were visible both in the Pt/Ir interlayer and in the electrodeposited Pt layer.
• cracks were visible in the interface between the Pt/Ir interlayer and the electrodeposited Pt layer. This indicated poor adhesion between the two coatings that resulted in coating delamination and reduced electrode lifetime.
• FIG. 7 illustrates the durability of the two samples under galvanostatic conditions. In the embodiment shown, the end of lifetime was reached when the potential reached 10 V. As seen from FIG. 7, the sample with the sALD Ir over a Ti/Ta interlayer had almost three times the lifetime compared to the Ti substrate without the Ti/Ta interlayer, i.e., Ti with only a sALD Ir layer. Accordingly, it was determined that the activity and stability of catalytic layers for electrodes was improved with the presence of a Ti/Ta metallic interlayer.
• PEM stack tests were performed in a single cell stack (ELIO, Hydron Energy B.V) with an active area of 10 cm 2 .
• a NAFION® 117 membrane with a cathode catalyst coated on one side was used. The loading of Pt on the single side catalyst coated membrane was 10 g/m 2 .
• Carbon paper (E35H, Freudenberg Performance Materials SE & Co. KG) was used as the cathode gas diffusion layer (GDL).
• Ti felt (2GDL10-0.25, Bekaert Fiber Technologies) with thickness of 0.25 mm was used as anode porous transport layer (PTL), with the anode catalyst coated on it.
• the substrate Prior to depositing the Ti/Ta interlayer, the substrate was etched for 10 minutes in 60 °C HC1. A mixed metal oxide of Ir and Ta was deposited on the anode PTL with an Ir loading of 20 g/m 2 .
• the interlayer consisted of an alloy of Ti/Ta between the anode PTL and MMO catalyst. Ultrapure water was used as the feed to the anode side of the stack. All measurements were done at 60 °C and 1 atm.
• FIG. 8 illustrates the stability of the two samples at a current density of 1 A/cm 2 .
• the addition of the Ti/Ta interlayer estimated to be about 1.5 pm thick, increased the stability of the PEM stack compared to the anode PTL and MMO catalyst without the Ti/Ta interlayer.
• a sample electrode was prepared using a Ti sheet substrate.
• a Ti/Ta interlayer was sputtered onto the surface of the Ti sheet.
• the interlayer was estimated to be about 200-300 nm thick.
• a layer of Ir was applied using sALD with the Ir precursor (EtCp)Ir(CHD).
• EtCp the Ir precursor
• CHD the Ir precursor
• the finished electrode sample was made into a cross-section using a focused ion beam.
• FIG. 9 illustrates an electron map of the vertical cross-section of the electrode sample.
• the lighter colored area of FIG. 9 illustrate the sALD Ir layer and the Ti/Ta interlayer and the dark colored area illustrates the underlying Ti substrate.
• SEM/EDS elemental maps for the electrode sample are illustrated in FIG. 10A-10C showing the distribution of the elements in each layer of the sample.
• Ti is located primarily in the underlying electrode substrate with a minor fraction of Ti found in the interlayer.
• the Ir was found in both the uppermost region of the electrode and throughout the underlying substrate following sALD.
• the Ta was found almost exclusively in the interlayer as a relatively narrow band, with little to no penetration onto the underlying substrate.
• the dark vertical line in FIG 9 represents the axis for the relative distribution plot of Ir and Ta shown in FIG. 11.
• the data was fitted with a simple Gaussian curve to show the general trends.
• FIG. 11 indicated that the Ir was concentrated at the edge of the Ta interlayer. Though the Ir layer was around 20 nm thick, it was observed that the Ir had a significant spread of hundreds of nm into the underlying layers. This effect was attributed to the SEM/EDS imaging technique.
• the term “plurality” refers to two or more items or components.
• the terms “comprising,” “including,” “carrying,” “having,” “containing,” and “involving,” whether in the written description or the claims and the like, are open-ended terms, i.e., to mean “including but not limited to.” Thus, the use of such terms is meant to encompass the items listed thereafter, and equivalents thereof, as well as additional items. Only the transitional phases “consisting of’ and “consisting essentially of,” are closed or semi-closed transitional phrases, respectively, with respect to the claims.

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