Preparation method and application of copper indium sulfide / copper sulfide composite photocatalyst
The composite photocatalyst that shares the chemical bond of sulfur atoms is formed through the in-situ epitaxial growth of CuInS2 and CuS, which solves the problems of low charge separation efficiency and high reaction energy barrier in the prior art, and achieves high selectivity and high efficiency in the preparation of C2H4 for CO2 and H2O.
Patent Information
- Application Number
- CN202510325824.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2025-08-01
AI Technical Summary
During the conversion of CO2 to C2H4, the charge separation efficiency is insufficient and the interface lattice matchability is poor, resulting in high reaction energy barrier and slow kinetic process, making it difficult to achieve high selectivity and efficient C2H4 generation.
Through in-situ epitaxial growth, CuInS2 is coupled with CuS to form a composite photocatalyst that shares chemical bonds of sulfur atoms, build high-efficiency charge transport channels and heteronuclear active sites, reduce the reaction energy barrier, and promote the C-C coupling reaction.
High selectivity and efficient CO2 and H2O preparation C2H4 was achieved, with a generation rate of 5.62 μmol·g-1·h-1, and the electron selectivity of C2H4 products reached 98.5%, which significantly improved the stability and selectivity of the catalyst.
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Figure CN120394042A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of composite nanomaterials, relates to photocatalysts, and particularly relates to a preparation method and application of a copper indium sulfide / copper sulfide composite photocatalyst. Technical Background
[0002] Ethylene (C2H4), as the world's largest industrial chemical, is widely used in many fields such as plastics, rubber, aerospace, and military industry. It is one of the important indicators to measure the development level of a country's chemical industry. China's current C2H4 production capacity ranks first in the world, and China's C2H4 production capacity will continue to grow in the future. At present, C2H4 mainly comes from coal chemical industry and naphtha cracking, which have problems such as serious CO2 emissions, high energy consumption, large pollution, and relatively harsh process conditions, and it is difficult to meet the development needs of the current low-carbon and green processes. Using solar energy to directly drive the photosynthesis of low-value resources carbon dioxide (CO2) and water (H2O) into C2H4 can not only achieve the zero-carbon preparation of C2H4, but also effectively alleviate the supply gap of C2H4 and the greenhouse effect, and is considered to be one of the important transformative technologies to promote the sustainable production of C2H4. However, the photocatalytic conversion of CO2 to C2H4 involves a complex 12-electron-proton coupling process, in which the slow kinetic reaction process and high thermodynamic energy barrier severely restrict the generation of highly selective C2H4. Developing and constructing a catalyst for efficiently driving the photosynthesis of CO2 and H2O to produce C2H4 is of great significance in the fields of catalytic reaction and catalyst engineering research. Among them, developing a composite photocatalyst that integrates efficient charge separation and matching active sites to promote the synergistic optimization of reaction dynamics / thermodynamics is the key to promoting the highly selective preparation of C2H4.
[0003] So far, the methods to improve charge transfer efficiency include element doping, noble metal cocatalyst loading, and heterostructure construction, etc. Among many strategies, constructing S-scheme heterojunction photocatalysts, as a low-complexity way to effectively promote carrier separation, most studies have focused on the van der Waals force interaction between different semiconductors and constructed S-scheme heterojunction photocatalysts by using electrostatic interaction. However, due to the poor interfacial lattice matching, the charge separation efficiency is still insufficient. Recent studies have found that constructing a charge transfer channel through chemical bond connection can effectively improve charge transfer kinetics and minimize the contact energy barrier between heterointerfaces. Therefore, rationally designing efficient charge transport channels and heteronuclear active sites to synergistically enhance carrier separation and directional utilization is crucial for achieving highly selective CO2 conversion to C2H4. The latest research shows that asymmetric active sites help reduce the dipole repulsion between adjacent intermediates, thereby effectively reducing the reaction energy barrier and promoting C-C coupling to form C2 products. Metal sulfides have become one of the most promising candidate materials for photocatalytic CO2 reduction due to their wide spectral response range, suitable bandgap structure, low cost, etc. Especially sulfides with dual-metal active sites have shown excellent catalytic performance in photocatalytic CO2 conversion to C2H4. However, the simultaneous construction of an efficient charge transport channel with chemical bond connection and heteronuclear active sites in a single photocatalytic system has not been fully studied. Therefore, developing a multi-metal composite catalyst is crucial for achieving highly selective photocatalytic CO2 and H2O conversion to C2H4.
[0004] The present invention aims to develop a heterostructure with chemical bond bonding, intending to couple CuInS2 with high lattice matching degree and CuS by in-situ epitaxial growth method to share sulfur atoms as a chemical bond bonding channel, which can greatly weaken the interfacial contact energy barrier and promote carrier separation. In addition, based on the adjacent heteronuclear active sites of Cu / In in the bimetallic sulfide CuInS2, it can reduce the mutual repulsion between reaction intermediates, promote the C-C coupling reaction, and then synergistically optimize the reaction thermodynamics of photocatalytic CO2 and H2O conversion to C2H4. Therefore, by constructing a photocatalytic system that synergistically optimizes carrier dynamics and reaction thermodynamics, it can provide a new perspective for the realization of highly selective photocatalytic CO2 and H2O conversion to C2H4. Summary of the Invention
[0005] In order to solve the deficiencies in the above technologies, the present invention aims to provide a preparation method of a composite photocatalyst (CuInS2 / CuS) with CuInS2 epitaxially grown on CuS.
[0006] Technical Solution
[0007] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst includes: adding an indium source and a copper source into an alcohol solvent and continuously stirring until dissolved, then adding a sulfur source, transferring to a hydrothermal reactor for heating, after the reaction is complete, cooling to room temperature, centrifugally washing with deionized water and ethanol multiple times, and drying to obtain; wherein, the molar and volume ratios of the indium source: copper source: sulfur source: alcohol solvent are 0.5 - 2 mmol: 1 - 6 mmol: 1.5 - 6 mmol: 15 - 60 mL, preferably 1 mmol: 2 mmol: 3 mmol: 30 mL; the heating temperature is 100 - 200 °C, preferably 180 °C; the heating duration is 10 - 30 h, preferably 18 h.
[0008] In a preferred disclosure example of the present invention, the indium source is a hydrochloride, nitrate or sulfate of indium, specifically indium chloride, indium nitrate, indium sulfate, preferably indium chloride.
[0009] In a preferred disclosure example of the present invention, the copper source is a nitrate, sulfate or hydrochloride of copper, specifically copper nitrate, cuprous nitrate, copper sulfate, cuprous sulfate, copper chloride or cuprous chloride, preferably copper chloride.
[0010] In a preferred disclosure example of the present invention, the alcohol solvent is ethanol, ethylene glycol, propanol, isopropanol, glycerol, butanol, etc., preferably ethylene glycol.
[0011] In a preferred disclosure example of the present invention, the sulfur source is a sulfide, thiosulfate, sulfate or sulfite, preferably thiosulfate, such as thioacetamide (C2H5NS).
[0012] The CuInS2 / CuS composite photocatalyst prepared according to the method of the present invention has a morphology of a flower ball composed of nanosheets, the thickness of the nanosheets is about 2 - 5 nm, and the diameter of the flower ball is about 2 - 5 μm.
[0013] Based on the difference in the precipitation equilibrium constants of CuInS2 and CuS in the present invention, there is a huge difference in the crystallization rates of the two in a homogeneous reaction system, resulting in the prior crystallization of CuS. At the same time, due to the high crystal plane matching between the two, CuInS2 tends to grow epitaxially on the surface of CuS, thereby constructing a CuInS2 / CuS composite photocatalyst with a shared sulfur atom structure.
[0014] The microscopic morphology structure of the CuInS2 / CuS prepared in the present invention is verified by a scanning electron microscope (SEM) and a transmission electron microscope (TEM), different crystal plane characteristics are proved by X-ray diffraction (XRD), the element binding energy is analyzed by X-ray photoelectron spectroscopy (XPS), and the optoelectronic properties are analyzed by photocurrent and steady-state fluorescence tests.
[0015] Another object of the present invention is to apply the prepared CuInS2 / CuS composite photocatalyst to photocatalytic preparation of C2H4 from CO2 and H2O.
[0016] Photocatalytic CO2 reduction performance test
[0017] (1) Disperse 2.0 mg of the photocatalyst on the surface of a microporous membrane with a radius of 2.35 cm. Add 0.5 mL of deionized water to the reaction system as a hole scavenger. In addition, conduct a vacuum treatment on the gas circulation system for 15 min, then fill it with high-purity CO2 gas (99.99%) to 90 kPa, conduct a vacuum treatment again, and then refill CO2 into the reaction system to maintain the pressure at 90 kPa;
[0018] (2) Use a 300 W xenon lamp as the light source, and the illumination wavelength range is greater than 420 nm. The gas products are detected by a gas chromatograph equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD). The generated gas is calibrated with a standard gas mixture, and its composition is qualitatively and quantitatively analyzed by retention time and peak intensity respectively.
[0019] Conduct a photocatalytic activity experiment by irradiating CO2 with a xenon lamp to reduce it. Determine the types of reduction products through the retention time of gas chromatography, and compare the measured peak area with the standard peak area to determine the CO2 reduction efficiency, so as to evaluate its photocatalytic CO2 reduction performance.
[0020] Beneficial effects
[0021] Based on the fast sulfur atom chemical bond as the electron transport channel and combined with the multi-heteronuclear site structure on the surface of CuInS2, the present invention effectively promotes the highly selective preparation of C2H4 by this composite catalyst. Description of the drawings
[0022] Figure 1 . (a) Schematic diagram of in-situ synthesis of CuInS2 / CuS; (b) SEM image of CuInS2 / CuS; (c) and (d) TEM images of CuInS2 / CuS; (e) EDS elemental mapping analysis image of CuInS2 / CuS.
[0023] Figure 2. (a) XRD pattern of CuInS2 / CuS; (b) XPS spectrum of CuInS2 / CuS.
[0024] Figure 3. (a) Comparison of photocurrent of CuInS2 / CuS, CuInS2, and CuS; (b) Comparison of fluorescence spectra of CuInS2 / CuS, CuInS2, and CuS.
[0025] Figure 4. (a) Comparison of photocatalytic activity data of CuInS2 / CuS, CuInS2, CuS, and CuInS2+CuS; (b) Comparison of photocatalytic selectivity data of CuInS2 / CuS, CuInS2, CuS, and CuInS2+CuS; (c) Photocatalytic stability data graph of CuInS2 / CuS.
[0026] Figure 5 . (a) XRD patterns of CuInS2 / CuS and CuInS2+CuS; (b) Enlarged local XRD pattern of CuInS2 / CuS and CuInS2+CuS. Detailed implementation mode
[0027] The present invention will be described in detail below with reference to the embodiments, so that those skilled in the art can better understand the present invention, but the present invention is not limited to the following embodiments.
[0028] Example 1
[0029] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst includes: adding 1 mmol of InCl3 and 2 mmol of CuCl2·2H2O to 30 mL of (CH2OH)2 and continuously stirring until dissolved, then adding 3 mmol of C2H5NS, transferring to a 100 mL hydrothermal autoclave and heating at 180 °C for 18 h. After the reaction is complete, cool to room temperature, wash centrifugally with deionized water and ethanol for multiple times, and dry to obtain the required composite catalyst.
[0030] The structural characterization of the prepared material is specifically analyzed as follows:
[0031] As Figure 1 shown in (a), the CuInS2 / CuS composite photocatalyst is directly constructed by a one-step hydrothermal method. Based on the solubility product difference between CuInS2 and CuS, there is a huge difference in the crystal growth rate. First, CuS precipitates rapidly during the hydrothermal reaction, and then CuInS2 grows epitaxially along CuS to construct a CuInS2 / CuS composite photocatalyst with sulfur chemical bond bridging. Figure 1 The TEM test in (b) shows a flower-like CuInS2 / CuS composite photocatalyst with aggregated nanosheets, and Figure 1 (c) and 1(d) further show a CuInS2 (112) crystal plane (lattice spacing of 0.31 nm) and a CuS (103) crystal plane (lattice spacing of 0.28 nm) with a high lattice matching degree, indicating that the composite sample has an efficient heterojunction charge transport channel. Figure 1(e) The EDS elemental Mapping image under high-angle annular dark field shows a uniform distribution of In, Cu, and S elements, further demonstrating the successful construction of a heterojunction with close connections.
[0032] As Figure 2 shown in (a), the XRD pattern of the prepared CuInS2 / CuS shows the characteristic crystal planes corresponding to the monomers CuInS2 and CuS, indicating the successful construction of this composite catalyst. Figure 2 (b) shows that compared with single CuInS2, CuInS2 / CuS shows an increase in the binding energy of the In element 3d 5 / 2 orbital, indicating that after the bonding of CuS and CuInS2, the peripheral electron distribution of In atoms shifts towards the overall CuS, indicating that a strong interaction is formed after the coupling of different semiconductor materials, which is conducive to the transfer of photo-generated charges and the separation of carriers.
[0033] As Figure 3 shown in (a), compared with single CuInS2 and CuS samples, CuInS2 / CuS has the highest photocurrent intensity, indicating that the heterojunction of this composite sample is conducive to the transfer of a higher amount of electrons to generate a stronger current response; in addition Figure 3 in (b), CuInS2 / CuS has the lowest fluorescence emission intensity, further indicating that the recombination rate of photo-generated carriers is significantly reduced under the promotion of a closely connected heterojunction.
[0034] The photocatalytic performance of the prepared material was tested, and the specific analysis is as follows:
[0035] As Figure 4 shown in (a), the prepared CuInS2 / CuS composite photocatalyst was applied to photocatalytic CO2 and H2O to prepare C2H4, which not only showed a C2H4 production rate of 5.62 μmol·g -1 ·h -1 , but also Figure 4 (b) shows that the electron selectivity of the C2H4 product is as high as 98.5%, both higher than the series of comparative samples (such as CuInS2, CuS, and the mechanical assembly sample of CuInS2 and CuS). In addition, Figure 4 (c) further shows the high stability of this composite catalyst, and the stable catalytic reaction time is up to 16 hours (h).
[0036] Comparative Example 1
[0037] A preparation method of a CuInS2 photocatalyst includes the following steps:
[0038] 1 mmol of InCl3 and 1 mmol of CuCl2·2H2O were added to 30 mL of (CH2OH)2 and stirred continuously until dissolved. Subsequently, 3 mmol of C2H5NS was added, and the mixture was transferred to a 100 mL hydrothermal reactor and heated at 200 °C for 12 h. After the reaction was complete, it was cooled to room temperature and centrifugally washed with deionized water and ethanol multiple times, and then dried to obtain the required composite catalyst.
[0039] As Figure 2 shown in Figure 3 (a), the crystal planes of the prepared material completely match the characteristic crystal planes of CuInS2, indicating the successful preparation of the monomer catalyst; in addition, -1 ·h -1 the C2H4 production rate of this monomer catalyst was 2.95 μmol·g
[0040] Comparative Example 2
[0041] A preparation method of a CuS photocatalyst includes the following steps:
[0042] 1 mmol of CuCl2·2H2O was added to 30 mL of (CH2OH)2 and stirred continuously until dissolved. Subsequently, 3 mmol of C2H5NS was added, and the mixture was transferred to a 100 mL hydrothermal reactor and heated at 180 °C for 18 h. After the reaction was complete, it was cooled to room temperature and centrifugally washed with deionized water and ethanol multiple times, and then dried to obtain the required composite catalyst.
[0043] As Figure 2 shown in Figure 3 (a), the crystal planes of the prepared material completely match the characteristic crystal planes of CuS, indicating the successful preparation of the monomer catalyst; in addition,
[0044] Comparative Example 3
[0045] A preparation method of a composite photocatalyst (CuInS2+CuS) mechanically assembled from CuInS2 and CuS includes the following steps:
[0046] 1 mmol of CuInS2 (Comparative Example 1) and 1 mmol of CuS (Comparative Example 2) were added to 10 mL of deionized water, sonicated for 30 minutes (min), and centrifugally dried to obtain a mechanically mixed sample.
[0047] Figure 5(a)shows that the composite CuInS2+CuS catalyst constructed by the mechanical mixing method is consistent with the characteristic crystal planes of in-situ grown CuInS2 / CuS, indicating that this method can successfully construct the composite CuInS2+CuS; however, compared with the mechanical mixing method, Figure 5 (b)shows that all the characteristic crystal planes of in-situ constructed CuInS2 / CuS shift to large angles, indicating that the interaction between CuInS2 and CuS is not van der Waals electrostatic interaction, further demonstrating the closely connected heterochemical bonding interface of the CuInS2 / CuS composite catalyst. Figure 4 (a)shows that the C2H4 production rate of the mechanically composite CuInS2+CuS photocatalyst is only 3.83 μmol·g -1 ·h -1 , Figure 4 (b)shows that the electron selectivity of the C2H4 product is 80.4%, further indicating that the chemically bonded CuInS2 / CuS has higher activity and selectivity in the conversion of CO2 to C2H4.
[0048] Example 2
[0049] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst, comprising: adding 1 mmol of indium nitrate (In(NO3)3) and 0.5 mmol of CuCl2·2H2O to 30 mL of (CH2OH)2 and continuously stirring until dissolved, then adding 3 mmol of C2H5NS, transferring to a 100 mL hydrothermal autoclave, heating at 180 °C, reacting for 18 h, after the reaction is complete, cooling to room temperature, centrifugally washing with deionized water and ethanol for multiple times, and drying to obtain the required composite catalyst.
[0050] The prepared CuInS2 / CuS composite photocatalyst is applied to photocatalytic preparation of C2H4 from CO2 and H2O, showing a C2H4 generation rate of 2.1 μmol·g -1 ·h -1 , and the electron selectivity of the C2H4 product is 92.1%.
[0051] Example 3
[0052] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst, comprising: adding 1 mmol of indium dichloride (InCl3) and 0.5 mmol of CuCl2·2H2O to 30 mL of (CH2OH)2 and continuously stirring until dissolved, then adding 3 mmol of C2H5NS, transferring to a 100 mL hydrothermal autoclave, heating at 180 °C, reacting for 18 h, after the reaction is complete, cooling to room temperature, centrifugally washing with deionized water and ethanol for multiple times, and drying to obtain the required composite catalyst.
[0053] The prepared CuInS2 / CuS composite photocatalyst is applied to photocatalytically prepare C2H4 from CO2 and H2O, showing a C2H4 generation rate of 3.8 μmol·g -1 ·h -1 and the electron selectivity of the C2H4 product is 87.6%.
[0054] Example 4
[0055] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst includes: adding 1 mmol of InCl3 and 1 mmol of copper nitrate (Cu(NO3)3) into 30 mL of (CH2OH)2 and continuously stirring until dissolved, then adding 3 mmol of C2H5NS, transferring to a 100 mL hydrothermal reactor, heating at 180 °C for 18 h. After the reaction is complete, cool to room temperature, wash by centrifugation with deionized water and ethanol for multiple times, and dry to obtain the required composite catalyst.
[0056] The prepared CuInS2 / CuS composite photocatalyst is applied to photocatalytically prepare C2H4 from CO2 and H2O, showing a C2H4 generation rate of 3.3 μmol·g -1 ·h -1 and the electron selectivity of the C2H4 product is 94.2%.
[0057] Example 5
[0058] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst includes: adding 1 mmol of InCl3 and 2.5 mmol of CuCl2·2H2O into 20 mL of (CH2OH)2 and continuously stirring until dissolved, then adding 3 mmol of sodium sulfide (Na2S), transferring to a 25 mL hydrothermal reactor, heating at 180 °C for 18 h. After the reaction is complete, cool to room temperature, wash by centrifugation with deionized water and ethanol for multiple times, and dry to obtain the required composite catalyst.
[0059] The prepared CuInS2 / CuS composite photocatalyst is applied to photocatalytically prepare C2H4 from CO2 and H2O, showing a C2H4 generation rate of 4.2 μmol·g -1 ·h -1 and the electron selectivity of the C2H4 product is 96.2%.
[0060] Example 6
[0061] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst, comprising: adding 1 mmol of InCl3 and 2 mmol of CuCl2·2H2O to 50 mL of (CH2OH)2 and continuously stirring until dissolved, then adding 5 mmol of sodium thiosulfate (Na2S2O3), transferring to a 100 mL hydrothermal autoclave and heating at 200 °C for 18 h. After the reaction is complete, cool to room temperature, wash by centrifugation with deionized water and ethanol for multiple times, and dry to obtain the required composite catalyst.
[0062] The prepared CuInS2 / CuS composite photocatalyst is applied to photocatalytic CO2 and H2O to prepare C2H4, showing a C2H4 production rate of 3.7 μmol·g -1 ·h -1 and a C2H4 product electron selectivity of 93.7%.
[0063] Example 7
[0064] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst, comprising: adding 1 mmol of InCl3 and 2 mmol of CuCl2·2H2O to 100 mL of (CH2OH)2 and continuously stirring until dissolved, then adding 5 mmol of C2H5NS, transferring to a 200 mL hydrothermal autoclave and heating at 200 °C for 18 h. After the reaction is complete, cool to room temperature, wash by centrifugation with deionized water and ethanol for multiple times, and dry to obtain the required composite catalyst.
[0065] The prepared CuInS2 / CuS composite photocatalyst is applied to photocatalytic CO2 and H2O to prepare C2H4, showing a C2H4 production rate of 3.7 μmol·g -1 ·h -1 and a C2H4 product electron selectivity of 88.2%.
[0066] Example 8
[0067] A preparation method of a copper indium sulfide / copper sulfide (CuInS2 / CuS) composite photocatalyst, comprising: adding 1 mmol of InCl3 and 2 mmol of CuCl2·2H2O to 20 mL of (CH2OH)2 and continuously stirring until dissolved, then adding 3 mmol of C2H5NS, transferring to a 25 mL hydrothermal autoclave and heating at 150 °C for 20 h. After the reaction is complete, cool to room temperature, wash by centrifugation with deionized water and ethanol for multiple times, and dry to obtain the required composite catalyst.
[0068] The prepared CuInS2 / CuS composite photocatalyst is applied to photocatalytic CO2 and H2O to prepare C2H4, showing a C2H4 generation rate of 4.6 μmol·g -1 ·h -1 , and the electron selectivity of the C2H4 product is 96.2%.
[0069] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the specification of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.
Claims
1. A preparation method of a copper indium sulfide / copper sulfide composite photocatalyst, characterized in that, Including: Add an indium source and a copper source into an alcohol solvent and continuously stir until dissolved. Subsequently, add a sulfur source, transfer it to a hydrothermal autoclave for heating. After the reaction is complete, cool it to room temperature, wash it centrifugally with deionized water and ethanol for multiple times, and then dry it to obtain the product. Among them, the molar and volume ratio of the indium source: copper source: sulfur source: alcohol solvent is 0.5 - 2 mmol: 1 - 6 mmol: 1.5 - 6 mmol: 15 - 60 mL, the heating temperature is 100 - 200 °C, and the heating duration is 10 - 30 h.
2. The preparation method of the copper indium sulfide / copper sulfide composite photocatalyst according to claim 1, characterized in that: The indium source is a hydrochloride, nitrate or sulfate of indium.
3. The preparation method of the copper indium sulfide / copper sulfide composite photocatalyst according to claim 1, characterized in that: The indium source is indium chloride, indium nitrate, indium sulfate, preferably indium chloride.
4. The preparation method of the copper indium sulfide / copper sulfide composite photocatalyst according to claim 1, characterized in that: The copper source is a nitrate, sulfate or hydrochloride of copper.
5. The preparation method of the copper indium sulfide / copper sulfide composite photocatalyst according to claim 1, characterized in that: The copper source is copper nitrate, cuprous nitrate, copper sulfate, cuprous sulfate, copper chloride or cuprous chloride, preferably copper chloride.
6. The preparation method of the copper indium sulfide / copper sulfide composite photocatalyst according to claim 1, wherein: The alcohol solvent is ethanol, ethylene glycol, propanol, isopropanol, glycerol or butanol, preferably ethylene glycol.
7. The preparation method of the copper indium sulfide / copper sulfide composite photocatalyst according to claim 1, characterized in that: The molar and volume ratio of the indium source: copper source: sulfur source: alcohol solvent is 1 mmol: 2 mmol: 3 mmol: 30 mL; the heating temperature is 180 °C; the heating duration is 18 h.
8. A copper indium sulfide / cuprous sulfide composite photocatalyst prepared by the method according to any one of claims 1 - 7.
9. The copper indium sulfide / copper sulfide composite photocatalyst according to claim 8, wherein: The morphology of the catalyst is a flower ball composed of nanosheets, the thickness of the nanosheets is 2 - 5 nm, and the diameter of the flower ball is 2 - 5 μm.
10. Use of the copper indium sulfide / copper sulfide composite photocatalyst according to claim 8 or 9, characterized in that: Apply it to photocatalytic preparation of C2H4 from CO2 and H2O.