CN103736501B - A kind of sulphur indium zinc composite and Synthesis and applications thereof with isomerism knot - Google Patents

Abstract

The invention discloses a kind of sulphur indium zinc composite and its preparation method and application with isomerism knot, belong to material preparation and light-catalysed technical field.Sulphur indium zinc composite prepared by the present invention has high-specific surface area, and the knot mutually formed between its six sides phase and Emission in Cubic can improve the separative efficiency of the photo-generated carrier of system effectively, thus improves ZnIn ₂s ₄visible light photocatalysis active, can efficient degradation organic pollution, photo-catalyst, photolysis water hydrogen and photocatalysis to selectively oxidize alcohols.This catalyst preparation process is simple, and cost is low, production process environmental protection, and catalyst stability is high, and realistic need of production has larger application potential.

Description

A kind of sulfur-indium-zinc composite material with heterogeneous junction and its preparation and application

technical field

The invention belongs to the technical field of material preparation and photocatalysis, and specifically relates to a sulfur-indium-zinc composite material with a heterogeneous junction and a preparation method and application thereof.

Background technique

Environmental pollution and energy crisis are major issues faced by human beings in the 21st century and need to be solved urgently. Due to its thorough reaction, mild reaction conditions, redox ability, high efficiency and energy saving, and no secondary pollution, photocatalytic technology has rapidly developed into a new technology that can use solar energy for environmental purification and energy conversion in recent years. It has become the most concerned research hotspot at present.

At present, _TiO2 -based semiconductor photocatalysts have key scientific and technological problems such as low photon quantum efficiency and low solar energy utilization, which greatly restrict their development. The key to the solution still lies in the photocatalyst. Therefore, scholars at home and abroad have done a lot of exploration work in improving the photon quantum efficiency of photocatalysts: for example, a lot of exploration has been done in the modification and modification of titanium dioxide photocatalysts, and achievements have been made. At the same time, it is also actively developing new non-titanium dioxide photocatalysts. Although these research works have greatly promoted the development of photocatalysis, and the quantum efficiency of photocatalysts has been improved for specific reactions, there are still some problems, such as doped ions are easy to form new recombination centers for photogenerated electrons and holes; modification sensitization The dye is unstable, etc. Therefore, researchers have focused their attention on designing and synthesizing highly efficient and energy-saving non- _TiO2 -based photocatalysts that directly utilize visible light.

Among them, multinary metal sulfide semiconductor photocatalysts have been widely studied due to their good light absorption properties and tunable band gap. Among the many reported visible light photocatalytic materials, ZnIn ₂ S ₄ exhibits good visible light photocatalytic performance due to its unique structure and physical and chemical properties, and overcomes the shortcomings of traditional sulfides that are easy to be photocorroded. has a good application prospect. At present, the research of ZnIn ₂ S ₄ mainly focuses on the control of morphology, crystal phase adjustment, doping modification, development of new preparation methods, and compounding with other semiconductor materials, in order to effectively improve its photocatalytic performance. However, the results of these studies are not ideal, so it is urgent to develop an effective means to enhance the photocatalytic performance of ZnIn ₂ S ₄ . Constructing heterojunctions between band-matched semiconductors has been proven to be an effective way to facilitate the optoelectronic separation of charges. However, the degree of lattice matching of heterogeneous materials is low, and it is difficult to combine stably and closely to form heterojunctions. Considering that ZnIn ₂ S ₄ has three typical structures of cubic phase, hexagonal phase and oblique hexahedron, and its different crystal phases have matching energy band structures, the present invention constructs a homogeneous heterogeneous junction in different phases of ZnIn ₂ S ₄ for the first time , the lattice is highly matched, and the efficient separation of photogenerated carriers is realized, so that ZnIn ₂ S ₄ exhibits extremely high photocatalytic performance under visible light irradiation.

Contents of the invention

The object of the present invention is to provide a sulfur-indium-zinc composite material with heterogeneous junction and its preparation method and application. The preparation process of the catalyst is simple, the cost is low, the production process is green and environment-friendly, the catalyst has high stability, meets the actual production needs, and has great application potential.

To achieve the above object, the present invention adopts the following technical solutions:

The specific surface area of the sulfur-indium-zinc composite material with heterogeneous junction of the present invention is 50-300m ² /g, and its appearance is nano-flaky, and clear lattice fringes can be observed in a high-resolution transmission electron microscope.

The present invention utilizes the hydrothermal method combined with the post-heat treatment process to prepare homogeneous and heterogeneous ZnIn ₂ S ₄ composites for the first time, and the prepared homogeneous and heterogeneous junctions can effectively improve the separation efficiency of photogenerated carriers in the system. Specifically include the following steps:

(1) A certain mass of ZnCl ₂ (10-20mmol), In(NO ₃ ) ₃ ·4.5H ₂ O (20-40mmol), thioacetamide (40-80mmol), Add polyvinylpyrrolidone (0-2g) into the polytetrafluoroethylene reactor, then add 70mL distilled water/ethanol/tetrachloromethane (volume ratio 1:1:0.2) mixture to the reactor, and place the reactor On a magnetic stirrer, adjust the pH value to 1-13. After stirring for 120 minutes, place it in an oven at 80-160°C for 2-36 hours. After the reaction kettle is cooled to room temperature, take out the mixture in the reaction kettle and centrifuge. The obtained precipitate was washed several times with distilled water and ethanol, and then dried in an oven at 60°C to obtain an orange powder precursor;

(2) Place the sulfur-indium-zinc precursor prepared above in a tube furnace for calcination under a nitrogen atmosphere. The temperature is controlled at 200-450°C and kept for 2-8 hours to obtain a heterogeneous heterogeneous sulfur-indium-zinc compound .

Significant advantage of the present invention is:

(1) For the first time in the present invention, the homogeneous and heterogeneous ZnIn ₂ S ₄ composite is prepared by combining the hydrothermal method with post-heat treatment. The prepared homogeneous and heterogeneous junction can effectively improve the separation efficiency of photogenerated carriers in the system, thereby improving The visible light photocatalytic activity of ZnIn ₂ S ₄ was investigated.

(2) Compared with single-phase ZnIn ₂ S ₄ prepared by other methods and common photocatalysts reported in the literature (such as TiO ₂ , Bi ₂ WO ₆ , etc.), its performance is better under visible light irradiation.

(3) The entire process of the present invention is simple and easy to control, the production process is green and environmentally friendly, low energy consumption, no need for complex and expensive equipment, mild synthesis conditions, low cost, good catalyst stability, and great application potential.

(3) The prepared homogeneous and heterogeneous ZnIn ₂ S ₄ composite can efficiently photocatalyze the treatment of printing and dyeing wastewater, photocatalytic sterilization, photolysis of water to produce hydrogen and selective oxidation of alcohols under sunlight irradiation, and has many advantages. good stability. In the photocatalytic reaction system, the photocatalyst has strong regenerability and high reuse rate, and has high practical value and application prospect.

Description of drawings

Fig. 1 is the X-ray photoelectron spectrum (XPS) of the homogeneous and heterogeneous ZnIn ₂ S ₄ composite obtained in Example 1.

Fig. 2 is the X-ray powder diffraction pattern (XRD) of the homogeneous and heterogeneous ZnIn ₂ S ₄ composite obtained in Example 1.

FIG. 3 is a transmission electron microscope image (TEM) of the homogeneous and heterogeneous ZnIn ₂ S ₄ composite obtained in Example 1. FIG.

Fig. 4 is a comparison diagram of the degradation effect of the homogeneous and heterogeneous ZnIn ₂ S ₄ composite obtained in Example 1, the pure phase ZnIn ₂ S ₄ and Bi ₂ WO ₆ on MO.

Detailed ways

Below are several embodiments of the present invention to further illustrate the present invention, but the present invention is not limited thereto.

Example 1

Add ZnCl ₂ (10mmol), In(NO ₃ ) ₃ ·4.5H ₂ O (20mmol), thioacetamide (40mmol), and polyvinylpyrrolidone (2g) into the polytetrafluoroethylene reactor respectively, and then to the reaction Add 70ml of distilled water/ethanol/tetrachloromethane (volume ratio 1:1:0.2) mixture into the kettle, place the reaction kettle on a magnetic stirrer, adjust the pH value to 2.3, stir for 120min, and place it in an oven at 120°C After the reactor was cooled to room temperature, the mixture in the reactor was taken out, centrifuged, and the obtained precipitate was washed several times with distilled water and ethanol, and then dried in an oven at 60°C to obtain an orange powder Precursor: The prepared sulfur-indium-zinc precursor was calcined in a tube furnace under a nitrogen atmosphere, the temperature was controlled at 400° C., and kept for 4 hours to obtain a homogeneous heterogeneous sulfur-indium-zinc composite.

Example 2

ZnCl ₂ (20mmol), In(NO ₃ ) ₃ ·4.5H ₂ O (40mmol), thioacetamide (80mmol), polyvinylpyrrolidone (0.2g) were added to the polytetrafluoroethylene reactor, and then Add 70ml of distilled water/ethanol/tetrachloromethane (volume ratio 1:1:0.2) mixture into the reaction kettle, place the reaction kettle on a magnetic stirrer, adjust the pH value to 2.3, stir for 120min, and place it in a 120°C React in the oven for 6 hours. After the reactor is cooled to room temperature, take out the mixture in the reactor and centrifuge. The precipitate obtained is washed several times with distilled water and ethanol, and dried in an oven at 60°C to obtain an orange powder. shape precursor; the prepared sulfur indium zinc precursor was placed in a tube furnace for calcination under a nitrogen atmosphere, the temperature was controlled at 400 °C, and kept for 4 hours to obtain a homogeneous heterogeneous sulfur indium zinc compound.

Example 3

Add ZnCl ₂ (10mmol), In(NO ₃ ) ₃ ·4.5H ₂ O (20mmol), thioacetamide (40mmol), and polyvinylpyrrolidone (1g) into the polytetrafluoroethylene reactor respectively, and then to the reaction Add 70ml of distilled water/ethanol/tetrachloromethane (volume ratio 1:1:0.2) mixture into the kettle, place the reaction kettle on a magnetic stirrer, adjust the pH value to 6, stir for 120min, and place it in an oven at 120°C After the reactor was cooled to room temperature, the mixture in the reactor was taken out, centrifuged, and the obtained precipitate was washed several times with distilled water and ethanol, and then dried in an oven at 60°C to obtain an orange powder Precursor: The prepared sulfur-indium-zinc precursor was calcined in a tube furnace under a nitrogen atmosphere, the temperature was controlled at 300° C., and kept for 4 hours to obtain a homogeneous heterogeneous sulfur-indium-zinc composite.

It can be seen from Figure 1 that Zn exists in the form of +2 valence, In exists in the form of +3 valence, and S exists in the form of -2 valence. At the same time, Zn/In/S has two binding energies, which are respectively related to the cubic phase and the hexagonal phase. The sulfur-indium-zinc phase corresponds, that is, the synthesized photocatalyst is a cubic phase and a hexagonal phase sulfur-indium-zinc composite.

Figure 2 is the XRD pattern of different ZnIn ₂ S ₄ samples, compared with the standard spectrum, it can be seen that (a) is hexagonal ZnIn ₂ S ₄ , (b) is cubic ZnIn ₂ S ₄ , (c) is cubic/hexagonal phase The ZnIn ₂ S ₄ complex is the sample described in the present invention.

Figure 3(a) is the transmission electron microscope picture of the sample. It can be seen from the figure that the sample is mainly composed of nanosheets; Figure 3(b) is the selected electron diffraction picture of the sample, and the diffraction points are formed in circles, which can be used to judge the sample It is polycrystalline; Figure 3(c) is a high-resolution transmission electron microscope image of the sample, from which clear lattice fringes can be observed, the interplanar spacing d=0.33nm and the (012) of cubic phase ZnIn ₂ S ₄ The crystal planes match, and the interplanar spacing d=0.20nm matches the (0110) crystal plane of the hexagonal phase ZnIn ₂ S ₄ , and an obvious phase junction is formed between the two phases. In other words, the present invention successfully prepared ZnIn ₂ S ₄ composites with heterogeneous junctions. Due to the different energy band structure properties on both sides of the junction, a space potential difference will be formed. The existence of this potential difference is conducive to the separation of electrons and holes, which can improve the efficiency of photocatalysis.

The photocatalytic performance test of heterogeneous heterogeneous sulfur indium zinc composite was characterized by the degradation of MO under xenon lamp irradiation. A batch reactor was adopted, and MO with a concentration of about 20ppm was used as the reaction substrate. A 300W xenon lamp was used as the light source, and the amount of the catalyst was 0.04g. Before turning on the light reaction, pre-adsorb to make MO adsorption-desorption balance on the catalyst, and then turn on the light to illuminate. It can be seen from Figure 4 that after turning on the light for 30 minutes, the degradation rate of MO by the heterogeneous heterogeneous sulfur indium zinc composite photocatalyst is as high as 100%. In contrast, the pure-phase ZnIn ₂ S ₄ catalyst has a relatively low degradation efficiency for MO under 60 min illumination time. At the same time, under the same conditions, it can be clearly seen that the homogeneous heterogeneous sulfur indium zinc composite prepared by the present invention has better performance than the currently developed photocatalyst Bi ₂ WO ₆ which responds to visible light and is relatively mature.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (4)

1. there is a preparation method for the sulphur indium zinc composite of isomerism knot, it is characterized in that: comprise the following steps:

(1) at 10-20mmolZnCl ₂, 20-40mmolIn (NO ₃) ₃4.5H ₂add 70mL mixed solvent in O, 40-80mmol thioacetamide and 0-2g polyvinylpyrrolidone, adjust ph=1-13, after magnetic agitation 120min, 80-160 DEG C of reaction 2-36h, is cooled to room temperature, centrifugal, sediment distilled water and ethanol wash for several times, dry to obtain presoma for 60 DEG C; The volume ratio 1:1:0.2 of distilled water, ethanol and tetrachloromethane in described mixed solvent;

(2) presoma that step (1) obtains is placed in tube furnace 200-450 DEG C of calcining 2-8h in a nitrogen atmosphere, obtains the described sulphur indium zinc composite with isomerism knot.

2. a sulphur indium zinc composite for what the method for claim 1 obtained have isomerism knot, is characterized in that: described sulphur indium zinc composite is by the ZnIn of Emission in Cubic ₂s ₄with the ZnIn of six side's phases ₂s ₄connecting and composing by tying mutually, utilizing knot mutually to realize out of phase ZnIn ₂s ₄the quick separating of upper photo-generated carrier, thus improve photocatalysis performance.

3. the sulphur indium zinc composite with isomerism knot according to claim 2, is characterized in that: the specific area of described sulphur indium zinc composite is 50-300m ²/ g, its pattern is nano-sheet.

4. there is an application for the sulphur indium zinc composite of isomerism knot as claimed in claim 2, it is characterized in that: the described sulphur indium zinc composite with isomerism knot is for degradable organic pollutant, photo-catalyst, photolysis water hydrogen and photocatalysis to selectively oxidize alcohols.