CuInS2-In2S3 nano-heterojunction catalyst, and preparation method and application thereof
By constructing a CuInS2-In2S3 nanoheterojunction catalyst, the problems of low current density and low selectivity of CuInS2 in the carbon dioxide reduction process were solved, and the effect of efficient carbon dioxide reduction to carbon monoxide was achieved.
Patent Information
- Application Number
- CN202310806712.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-30
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2043-06-30
AI Technical Summary
Existing CuInS2 catalysts suffer from low current density, low product formation rate, and low selectivity during carbon dioxide reduction, which limits their catalytic activity and applications.
Using Cu1.94S nanocrystals as templates, CuInS2-In2S3 nanoheterojunction catalysts were prepared by cation exchange and seed growth methods. Cu1.94S nanocrystals were used to exchange cations with indium ions and combine with sulfur powder to form In2S3 particles, thus constructing a nanoheterostructure.
It improves the selectivity and catalytic activity of carbon dioxide reduction products, significantly enhances catalytic efficiency, and has a stable catalyst structure, making it suitable for applications that reduce carbon dioxide to carbon monoxide.
Smart Images
Figure CN116603542B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The embodiment of the present application belongs to the technical field of functional materials, and particularly relates to a CuInS2-In2S3 nano-heterojunction catalyst and a preparation method and application thereof. BACKGROUND
[0002] With the increasingly urgent global energy and environmental situation, the use of new materials and new processes to improve energy utilization efficiency and deepen energy structure has become one of the current research hotspots. Among them, the electrocatalytic reduction of carbon dioxide provides feasibility for realizing carbon neutral energy cycle. However, before the electrocatalytic reduction of carbon dioxide technology is applied in industry, there are still some bottleneck problems to be solved, such as low conversion efficiency, low selectivity and low reaction rate.
[0003] At present, in the prior art, noble metal catalysts, composite materials and the like are usually required to activate carbon dioxide into CO* or other intermediates, so as to convert carbon dioxide into useful fuels. In order to meet the production and research needs, more and more types of composite materials are designed, for example, CuInS2 as a common semiconductor material is often used in applications such as photocatalytic splitting of water to produce H2 or electrocatalytic CO2 reduction, and has application prospects in the fields of catalysis, energy storage, gas separation and the like.
[0004] However, the prior art in the above has the following defects: CuInS2 in CO2 reduction catalysis faces many problems: low product formation rate caused by small current density, which limits the catalytic activity; in addition, low selectivity leads to single reduction product, which affects the actual application. SUMMARY
[0005] The purpose of the embodiment of the present application is to provide a CuInS2-In2S3 nano-heterojunction catalyst, which is prepared by using Cu 1.94 S nanocrystals as a template and adopting a method of cation exchange and seed growth to obtain the CuInS2-In2S3 nano-heterojunction catalyst, so as to solve the problems of low product selectivity and small current density of CuInS2 in CO2 reduction, which limit its catalytic activity and application in the catalytic process. The prepared CuInS2-In2S3 nano-heterojunction catalyst has stable structure and stable product performance, and exhibits good carbon dioxide reduction catalytic activity and high catalytic efficiency.
[0006] To achieve the above purpose, the embodiment of the present application provides the following technical scheme:
[0007] A CuInS2-In2S3 nano-heterojunction catalyst comprises the following raw materials: indium chloride, octadecene, oleylamine, sulfur powder and an appropriate amount of Cu 1.94S nanocrystals; wherein, the Cu 1.94 The S nanocrystals are prepared by taking copper chloride, copper nitrate, tertiary dodecanethiol and an appropriate amount of dispersion medium as raw materials.
[0008] In the embodiment of the present application, the Cu 1.94 The S nanocrystals are used as templates to prepare the CuInS2-In2S3 nano-heterojunction catalyst by cation exchange and seed growth, and the preparation method is simple and controllable. The product selectivity of the catalyst in the CO2 reduction is greatly improved compared with CuInS2, and the catalyst has a wide prospect in practical application.
[0009] As a preferred embodiment of the above technical solution, the Cu 1.94 The preparation steps of the S nanocrystals are as follows: copper chloride, copper nitrate, oleylamine, octadecene and tertiary dodecanethiol are mixed by magnetic stirring, heated and reacted at a set temperature, and then the prepared product is centrifuged and washed to obtain a solution.
[0010] Another object of the embodiment of the present application is to provide a preparation method of the CuInS2-In2S3 nano-heterojunction catalyst, and the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst specifically comprises the following steps:
[0011] 1) The indium chloride, sulfur powder, octadecene, oleylamine and Cu 1.94 S nanocrystals are mixed and heated to a reaction temperature, and reacted for a period of time to obtain a reaction solution;
[0012] 2) The reaction solution obtained in step 1) is cooled to room temperature, centrifuged, washed and dried to obtain the CuInS2-In2S3 nano-heterojunction catalyst, i.e. the CuInS2-In2S3 nano-heterojunction catalyst.
[0013] In one embodiment of the present application, the Cu 1.94 The preparation process of the S nanocrystals is as follows:
[0014] S21: CuCl2 and Cu(NO3)2 are stirred and dissolved in octadecene and oleylamine, and heated and reacted, 1-2 mL of tertiary dodecanethiol is added when the reaction temperature rises to 120 DEG C;
[0015] S22: After the reaction in step S21 is stopped, the reaction solution is cooled to room temperature and taken out;
[0016] S23: The product in step S22 is washed with n-hexane and ethanol in sequence, and dried to obtain the Cu 1.94 S nanocrystals.
[0017] Another object of the present application is to provide a CuInS2-In2S3 nano-heterojunction catalyst prepared by the above preparation method and application of the CuInS2-In2S3 nano-heterojunction catalyst in CO production by reduction of carbon dioxide.
[0018] Compared with the prior art, the present application has the following advantages:
[0019] The CuInS2-In2S3 nano-heterojunction catalyst provided by the present application is prepared by using indium chloride, octadecene, oleylamine, sulfur powder and appropriate Cu 1.94 S nanocrystals as raw materials, cation exchange and seed growth method, using Cu 1.94 S nanocrystals as templates, cation exchange with indium ions and combination of indium ions with sulfur powder added in the reaction system, nucleation of In2S3 particles on Cu 1.94 S nanocrystals, and finally preparing the CuInS2-In2S3 nano-heterojunction catalyst. The catalyst has stable structure and stable product performance, and the selectivity of the CO2 reduction product is greatly improved compared with CuInS2, solving the problem of low product selectivity and small current density of CuInS2 in CO2 reduction, which limits its catalytic activity and application in the catalytic process. Moreover, the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst provided by the present application can be controlled, and compared with the method in the prior art, it is simple and efficient, and has a broad market prospect. BRIEF DESCRIPTION OF DRAWINGS
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application.
[0021] Figure 1 The transmission electron microscope (TEM) characterization photo of Cu 1.94 S nanocrystals prepared in the present application embodiment 1.
[0022] Figure 2 The transmission electron microscope (TEM) characterization photo of CuInS2-In2S3 nano-heterojunction catalyst prepared in the present application embodiment 1.
[0023] Figure 3 The XRD chart of CuInS2-In2S3 nano-heterojunction catalyst, Cu 1.94 S nanocrystals prepared in the present application embodiment 1.
[0024] Figure 4CuInS2-In2S3 nano-heterojunction catalyst and CuInS2, In2S3 and Cu 1.94 Faraday efficiency diagram of carbon dioxide reduction to CO at different voltages.
[0025] Figure 5 CuInS2-In2S3 nano-heterojunction catalyst and CuInS2, In2S3 and Cu 1.94 Current density diagram of electrocatalysis of CuInS2-In2S3 nano-heterojunction catalyst and CuInS2, In2S3 and Cu DETAILED DESCRIPTION
[0026] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clear, the following will be combined with the embodiments of the present application and the drawings, and the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the following embodiments will help the person skilled in the art to further understand the embodiments of the present application, but do not limit the embodiments of the present application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the embodiments of the present application, a number of modifications and improvements can be made. These all belong to the protection scope of the embodiments of the present application.
[0027] The specific implementation of the present application will be described in detail below in combination with specific embodiments.
[0028] First of all, it should be pointed out that CuInS2 is a common semiconductor material, which is often used in photocatalytic splitting of water to produce H2 or electrocatalytic reduction of CO2, etc. For example, in the prior art, by using CuInS2 as a catalytic material, CO2 can be effectively electrocatalytically reduced to carbon monoxide (CO).
[0029] However, CuInS2 has many problems when it is used to catalyze CO2 reduction: low product formation rate caused by low current density, which reduces the catalytic efficiency; in addition, low selectivity leads to single reduction product.
[0030] Therefore, in order to solve the problems in the prior art, the present application is studied in a series of ways in order to compensate for this deficiency by modifying the nanostructure.
[0031] Therefore, the embodiments of the present application provide a CuInS2-In2S3 nano-heterojunction catalyst, specifically a CuInS2-In2S3 nano-heterojunction catalyst which exhibits good carbon dioxide reduction catalytic activity, and the preparation of the nano-heterojunction catalyst uses the following raw materials:
[0032] Indium chloride, octadecene, oleylamine, sulfur powder and appropriate amount of Cu 1.94 S nanocrystals; wherein the Cu 1.94The S nanocrystal is prepared by taking copper chloride, copper nitrate, tertiary dodecanethiol and an appropriate amount of dispersion medium as raw materials.
[0033] Therefore, the application is prepared by the method of cation exchange and seed growth, and Cu 1.94 The S nanocrystal is used as a template, and cation exchange is performed with indium ions, and the indium ions are combined with sulfur powder added in the reaction system to form In2S3 particles on the Cu 1.94 The S nanocrystal is used as a template, and cation exchange is performed with indium ions, and the indium ions are combined with sulfur powder added in the reaction system to form In2S3 particles on the Cu
[0034] In addition, it should be noted that CuInS2 has the problem of catalyst instability during long-time testing when performing CO2 conversion catalysis. Generally speaking, the method of constructing a nano-heterostructure and utilizing the synergistic effect between different components to improve the catalytic performance of a single material is relatively effective. In the past decade, transition metal sulfides have attracted much attention due to their unique physical and chemical properties. In2S3 is a common transition metal sulfide, and in recent years, its synthesis and catalytic performance have been widely studied. In comparison with Cd, Pb and other transition metals, In has low toxicity, and it has strong selectivity for CO and formic acid in the process of electrocatalytic CO2 conversion, but its selectivity cannot meet the requirements of actual production and application.
[0035] Therefore, the application is prepared by the method of cation exchange and seed growth, and Cu 1.94 The S nanocrystal is used as a template, and cation exchange is performed with indium ions, and the indium ions are combined with sulfur powder added in the reaction system to form In2S3 particles on the Cu
[0036] Further preferably, the dispersion medium can be any one or more of octadecene and oleylamine. Generally speaking, in order to improve the dissolution effect of copper chloride and copper nitrate, an appropriate amount of octadecene and oleylamine can be used as the dispersion medium.
[0037] Further preferably, the Cu 1.94The preparation steps of the S nanocrystal are as follows: the copper chloride, copper nitrate, oleylamine, octadecene, and tert-dodecanethiol are mixed by magnetic stirring, and then heated and reacted at a set temperature, and then the prepared product is centrifuged and washed with a solution to obtain the product. The addition amount of copper chloride and copper nitrate is 0.4-0.5:0.02-0.07 in molar ratio, preferably, the addition amount of copper chloride (CuCl2) and copper nitrate (Cu(NO3)2) is 0.45:0.05 in molar ratio.
[0038] Further preferably, in the preparation of the Cu 1.94 In the preparation of the S nanocrystal, the copper chloride (CuCl2) and copper nitrate (Cu(NO3)2) are dissolved and heated by stirring with octadecene and oleylamine, and then 1-2 mL of tert-dodecanethiol is added for reaction. The reaction temperature is 120-190°C, and further preferably 160-190°C, and the reaction time is 15-20 min.
[0039] Further preferably, in the preparation of the Cu 1.94 The preparation method of the S nanocrystal is as follows:
[0040] S1: 0.45 mmol of CuCl2 and 0.05 mmol of Cu(NO3)2 are dissolved in a three-necked flask with 5 mL of octadecene and an appropriate amount of oleylamine and heated to form a mixture;
[0041] S2: the mixture in step S1 is heated to 120°C, 1.9 mL of tert-dodecanethiol is added, and the solution is quickly heated from blue to yellow;
[0042] S3: the solution in step S2 is cooled to room temperature, and the product is washed with n-hexane and ethanol in sequence to obtain the reaction product;
[0043] S4: the obtained reaction product in step S3 is dried to obtain Cu 1.94 S nanocrystal.
[0044] Further preferably, in the raw materials of the CuInS2-In2S3 nanoheterojunction catalyst, the indium chloride is 0.05-0.3 mmol, the sulfur powder is 5-25 mg, the oleylamine is 0.4-1.2 mL, and the octadecene is 2-12 mL.
[0045] Further preferably, in the raw materials of the CuInS2-In2S3 nanoheterojunction catalyst, the indium chloride is 0.1-0.2 mmol, the sulfur powder is 10-20 mg, the oleylamine is 0.5-1 mL, and the octadecene is 5-10 mL.
[0046] As the preferred solution of the above technical scheme, in the raw material of the CuInS2-In2S3 nano-heterojunction catalyst, generally, the indium chloride is 0.1 mmol, the sulfur powder is 10 mg, the oleylamine is 1 mL, and the octadecene is 6 mL.
[0047] The embodiment of the present application also provides a preparation method of the CuInS2-In2S3 nano-heterojunction catalyst, which specifically comprises the following steps:
[0048] 1) proportionally mix indium chloride, sulfur powder, octadecene, oleylamine, Cu 1.94 S nanocrystals, heat to a reaction temperature, react for a period of time, and obtain a reaction solution;
[0049] 2) cool the reaction solution obtained in step 1) to room temperature, centrifuge, wash, and dry to obtain the CuInS2-In2S3 nano-heterojunction catalyst.
[0050] It should be noted that in the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst, Cu 1.94 S nanocrystals need to be prepared first, that is, in the first step, copper chloride, copper nitrate, oleylamine, octadecene, and tert-dodecanethiol are mixed by magnetic stirring, heating is performed at a set temperature, and then the prepared product is centrifuged and washed to obtain Cu 1.94 S nanocrystals. In the second step, Cu 1.94 S nanocrystals, sulfur powder, oleylamine, and octadecene are mixed by magnetic stirring, heating is performed at a set temperature, and the CuInS2-In2S3 nano-heterojunction catalyst is prepared. The preparation method of the present application is simple and controllable, the structure of the prepared CuInS2-In2S3 nano-heterojunction catalyst is stable, the product performance is stable, and the catalyst exhibits good carbon dioxide reduction catalytic activity and high catalytic efficiency.
[0051] As the preferred solution of the above technical scheme, in the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst, the reaction temperature is 190-210°C.
[0052] As the preferred solution of the above technical scheme, in the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst, the reaction time is 10-30 min.
[0053] Further preferably, the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst comprises the following steps:
[0054] S1: add 0.1 mmol of indium chloride, 6 mL of octadecene, 1 mL of oleylamine, 10 mg of sulfur powder, and an appropriate amount of Cu1.94 S nanocrystals, setting the reaction temperature to heat the reaction;
[0055] S2: when the solution in S1 reaches 190 DEG C, react at this temperature for 20 minutes to obtain a reaction solution;
[0056] S3: when the reaction solution in S2 is cooled to room temperature, remove it and wash the product with n-hexane and ethanol in sequence and centrifuge;
[0057] S4: after drying the product in S3, a CuInS2-In2S3 nano-heterojunction catalyst can be prepared.
[0058] The embodiment of the present application also provides a CuInS2-In2S3 nano-heterojunction catalyst prepared by the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst. 1.94 S nanocrystals are used as templates, and the indium ions are subjected to cation exchange and combined with the sulfur powder added in the reaction system to form In2S3 particles on the CuInS2 nanocrystals. 1.94 S nanocrystals, and finally a CuInS2-In2S3 nano-heterojunction catalyst is prepared.
[0059] The embodiment of the present application also provides an application of the CuInS2-In2S3 nano-heterojunction catalyst in carbon dioxide reduction.
[0060] Further, in the application, the CuInS2-In2S3 nano-heterojunction catalyst prepared by the preparation method can be used for carbon dioxide reduction to produce CO, and the selectivity of the product is greatly improved compared with that of CuInS2.
[0061] The technical effects of the CuInS2-In2S3 nano-heterojunction catalyst of the embodiment of the present application are further described below by listing specific embodiments.
[0062] Embodiment 1
[0063] A CuInS2-In2S3 nano-heterojunction catalyst, and a preparation method thereof, includes the following steps:
[0064] 1. preparing CuInS2 nanocrystals 1.94 S nanocrystals
[0065] S1: 0.45 mmol of CuCl2 and 0.05 mmol of Cu(NO3)2 are dissolved in a three-necked flask with 5 mL of octadecene and an appropriate amount of oleylamine and heated;
[0066] S2: Heat the S1 mixture to 120°C, add 1.9 mL of tert-dodecyl mercaptan, and the solution changes from blue to yellow after rapid heating;
[0067] S3: After cooling the solution of S2 to room temperature, remove it and wash the product with hexane and ethanol successively.
[0068] S4: Dry the reactants from S3 to obtain Cu. 1.94 S nanocrystals; the obtained Cu 1.94 S nanocrystals were characterized by TEM, and the characterization results are shown in the figure. Figure 1 .from Figure 1 Cu can be clearly seen 1.94 S nanocrystals have a disk-like structure, therefore they can also be called Cu. 1.94 S-nanofas.
[0069] 2. Preparation of CuInS2-In2S3 heterojunction catalyst
[0070] S1: Add 0.1 mmol of indium chloride, 6 mL of octadecene, 1 mL of oleylamine, 10 mg of sulfur powder, and an appropriate amount of Cu to a three-necked flask. 1.94 S-nano disks are used to set the temperature for heating the reaction.
[0071] S2: When the solution in S1 reaches 190℃, react at that temperature for 20 minutes;
[0072] S3: After cooling the solution in S2 to room temperature, remove it and wash and centrifuge the product several times with hexane and ethanol.
[0073] S4: After drying the product in S3, CuInS2-In2S3 nanoheterojunction catalyst is obtained.
[0074] Example 2
[0075] Compared to Example 1, except for the preparation of Cu 1.94 The process for S nanocrystals was the same as in Example 1, except that 0.45 mmol of CuCl2 and 0.05 mmol of Cu(NO3)2 were dissolved in 5 mL of octadecene.
[0076] Example 3
[0077] Compared to Example 1, except for the preparation of Cu 1.94 The process for S nanocrystals was the same as in Example 1, except that 0.45 mmol of CuCl2 and 0.05 mmol of Cu(NO3)2 were dissolved in 5 mL of oleylamine.
[0078] Example 4
[0079] Compared to Example 1, except for the preparation of Cu1.94 S nanocrystals is prepared by using 0.4 mmol of CuCl2, 0.02 mmol of Cu(NO3)2, and other conditions are the same as in Example 1.
[0080] Example 5
[0081] Compared with Example 1, except that CuInS2-In2S3 nanoheterojunction catalyst is prepared by using 0.2 mmol of indium chloride, 5 mL of octadecene, 0.5 mL of oleylamine, 20 mg of sulfur powder and an appropriate amount of Cu 1.94 S nanocrystals is prepared by using 0.5 mmol of CuCl2, 0.07 mmol of Cu(NO3)2, and other conditions are the same as in Example 1.
[0082] Example 6
[0083] Compared with Example 1, except that CuInS2-In2S3 nanoheterojunction catalyst is prepared by using 0.2 mmol of indium chloride, 5 mL of octadecene, 0.5 mL of oleylamine, 20 mg of sulfur powder and an appropriate amount of Cu 1.94 S nanodisks (Cu 1.94 The amount of CuInS2-In2S3 nanoheterojunction catalyst can be added as needed, and preferably, the amount of CuInS2-In2S3 nanoheterojunction catalyst prepared in Example 1 is added. 1.94 S nanocrystals is prepared by using 0.5 mmol of CuCl2, 0.07 mmol of Cu(NO3)2, and other conditions are the same as in Example 1.
[0084] Example 7
[0085] Compared with Example 1, except that CuInS2-In2S3 nanoheterojunction catalyst is prepared by using 0.2 mmol of indium chloride, 5 mL of octadecene, 0.5 mL of oleylamine, 20 mg of sulfur powder and an appropriate amount of Cu 1.94 S nanodisks (Cu 1.94 The amount of CuInS2-In2S3 nanoheterojunction catalyst can be added as needed, and preferably, the amount of CuInS2-In2S3 nanoheterojunction catalyst prepared in Example 1 is added. 1.94 S nanocrystals is prepared by using 0.5 mmol of CuCl2, 0.07 mmol of Cu(NO3)2, and other conditions are the same as in Example 1.
[0086] Example 8
[0087] Compared with Example 1, except that CuInS2-In2S3 nanoheterojunction catalyst is prepared by using 0.2 mmol of indium chloride, 5 mL of octadecene, 0.5 mL of oleylamine, 20 mg of sulfur powder and an appropriate amount of Cu 1.94 S nanodisks (Cu 1.94 The amount of CuInS2-In2S3 nanoheterojunction catalyst can be added as needed, and preferably, the amount of CuInS2-In2S3 nanoheterojunction catalyst prepared in Example 1 is added. 1.94 S nanocrystals is prepared by using 0.5 mmol of CuCl2, 0.07 mmol of Cu(NO3)2, and other conditions are the same as in Example 1.
[0088] Example 9
[0089] In this example, CuInS2-In2S3 nanoheterojunction catalyst prepared in Example 1 is used. 1.94S nanocrystals were characterized by TEM, and the characterization results are shown in the figure. Figure 1 .from Figure 1 Cu can be clearly seen 1.94 The S nanocrystal structure is disk-shaped. Meanwhile, the CuInS2-In2S3 nanoheterojunction catalyst prepared in Example 1 was characterized by TEM. Figure 2 These are TEM characterization images of the prepared CuInS2-In2S3 nanoheterojunction catalyst. Figure 2 It can be seen that the edge of the CuInS2 nanodiscs is surrounded by a ring of indium sulfide nanoparticles. Therefore, it can be seen that the prepared CuInS2-In2S3 nanoheterojunction catalyst is composed of Cu... 1.94 Using S nanodisks as templates, cation exchange occurs between indium ions and indium ions, which then bind to sulfur powder added to the reaction system. 1.94 In2S3 particles are formed on the S nanodiscs.
[0090] In addition, the Cu obtained in Example 1 1.94 S nanocrystals and CuInS2-In2S3 nanoheterojunction catalysts were characterized by XRD. Figure 3 CuInS2-In2S3 nanoheterojunction catalyst, Cu 1.94 XRD pattern of S. As shown in the figure, the black peaks at the top represent the CuInS2-In2S3 heterojunction, and their peaks correspond to the standard cards for CuInS2 and In2S3. The gray peaks at the bottom represent Cu... 1.94 The peaks of S nanodisks can interact with Cu. 1.94 The standard card for S corresponds to this.
[0091] Example 10
[0092] To further understand the material properties, the CuInS2-In2S3 nanoheterojunction catalyst prepared in Example 1 will be compared with existing Cu... 1.94 S (where Cu) 1.94 S can be prepared directly using the preparation method in Example 1. 1.94 A comparison of catalytic efficiency was made between S nanocrystals, In2S3 and CuInS2 materials.
[0093] Specifically, weigh out equal stoichiometric amounts of Cu. 1.94S, In2S3, CuInS2 and CuInS2-In2S3 nanoheterojunction catalyst prepared in Example 1 were dissolved in a certain amount of isopropanol, and a small amount of nafion solution was added as a binder, and ultrasonic was used for half an hour to make them uniformly dispersed, and then a gas gun was used to uniformly spray them on the gas diffusion electrode, 1M KOH was used as the electrolyte, and the above four kinds of catalysts were tested in the CO2 reduction flow cell system respectively, and the gaseous products were analyzed by gas chromatography (GC), and the liquid products were detected by nuclear magnetic resonance (NMR). The test results are shown in Figure 4 , which shows the distribution of main CO2 reduction products at different potentials and reversible hydrogen electrode (RHE). The best catalyst (CuInS2-In2S3) has a CO faradic efficiency as high as 63.2% at a voltage of-1.0V. As Figure 5 shows that the current density of CuInS2-In2S3 is 58mA / cm 2 at this potential (-1.0V), which is higher than that of Cu 1.94 S, In2S3 and CuInS2. It can be seen that the CO faradic efficiency of CuInS2-In2S3 nanoheterojunction catalyst prepared in Example 1 is obviously higher than that of pure Cu 1.94 S, In2S3 and CuInS2 in the CO2 reduction test, which shows that the CuInS2-In2S3 nanoheterojunction catalyst prepared by the application has the best effect in the CO2 reduction test, has excellent selectivity, and has higher catalytic efficiency.
[0094] From the previous data, it can be seen that, by the method of cation exchange and seed growth, Cu 1.94 S nanodisks are used as templates, and cation exchange is carried out with indium ions, and the indium ions combine with the sulfur powder added in the reaction system to form In2S3 particles on the Cu 1.94 S nanodisks, and finally the CuInS2-In2S3 nanoheterojunction catalyst is prepared. The selectivity of the catalyst for CO2 reduction products is greatly improved compared with CuInS2. The preparation method is simple and controllable.
[0095] It should be noted that CuInS2 is a common semiconductor material, which is often used in applications such as photocatalytic splitting of water to produce H2 or electrocatalytic CO2 reduction. It can effectively catalyze the electroreduction of CO2 to carbon monoxide (CO). However, CuInS2 faces many problems when it is used for CO2 reduction catalysis: low product formation rate caused by low current density; low selectivity leads to single reduction product; and the catalyst is unstable during long-term testing. The application embodiment uses Cu 1.94The CuInS2-In2S3 nano-heterojunction catalyst is prepared by cation exchange and seed growth using S nanodisks as a template, and has the advantages of simple preparation method, high controllability, stable structure, stable catalytic performance, and higher catalytic efficiency of S, In2S3 and CuInS2, higher catalytic selectivity and activity, and higher catalytic efficiency. 1.94 The CuInS2-In2S3 nano-heterojunction catalyst is prepared by cation exchange and seed growth using S nanodisks as a template, and has the advantages of simple preparation method, high controllability, stable structure, stable catalytic performance, and higher catalytic efficiency of S, In2S3 and CuInS2, higher catalytic selectivity and activity, and higher catalytic efficiency.
[0096] The above describes the preferred embodiments of the present application in detail, describes the basic principles, main features and advantages of the present application. However, those skilled in the art should understand that the embodiments of the present application are not limited to the above embodiments, and the above embodiments and descriptions described in the specification are only preferred examples of the present application, and are not intended to limit the present application. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the purpose of the embodiments of the present application. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or changes derived therefrom are still within the protection scope of the embodiments of the present application.
Claims
1. A CuInS2-In2S3 nano-heterojunction catalyst, characterized in that, The CuInS2-In2S3 nano-heterojunction catalyst is prepared by using the following raw materials: indium chloride, octadecene, oleylamine, sulfur powder and appropriate amount of Cu 1.94 S nanocrystals; wherein the Cu 1.94 S nanocrystals are prepared by using copper chloride, copper nitrate, tertiary dodecanethiol and appropriate amount of dispersion medium as raw materials; when the Cu 1.94 S nanocrystals are prepared, copper chloride (CuCl2) and copper nitrate (Cu(NO3)2) are dissolved and heated by stirring with octadecene and oleylamine, and then 1-2 mL of tertiary dodecanethiol is added for reaction when the reaction temperature rises to a certain temperature, the reaction temperature is 160-190°C, and the reaction time is 15-20 min. 2.The CuInS 2-In 2S 3 nano-heterojunction catalyst of claim 1, wherein, When the Cu 1.94 S nanocrystals are prepared, the amount of copper chloride and copper nitrate added is 0.4-0.5:0.02-0.07 in molar ratio. 3.The CuInS 2-In 2S 3 nano-heterojunction catalyst of claim 1, wherein, In the raw materials of the CuInS2-In2S3 nano-heterojunction catalyst, the indium chloride is 0.05-0.3 mmol, the sulfur powder is 5-25 mg, the oleylamine is 0.4-1.2 mL, and the octadecene is 2-12 mL.
4. The CuInS2-In2S3 nanoheterojunction catalyst according to claim 3, wherein, In the raw materials of the CuInS2-In2S3 nano-heterojunction catalyst, the indium chloride is 0.1-0.2 mmol, the sulfur powder is 10-20 mg, the oleylamine is 0.5-1 mL, and the octadecene is 5-10 mL.
5. A method for preparing CuInS2-In2S3 nano-heterojunction catalyst according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: 1) In proportion indium chloride, sulfur powder, octadecene, oleylamine, Cu 1.94 S nanocrystals are mixed and heated to the reaction temperature, and the reaction is carried out for a period of time to obtain a reaction solution; 2) cooling the reaction solution obtained in step 1) to room temperature, centrifuging, washing, and drying to obtain the CuInS2-In2S3 nano-heterojunction catalyst.
6. The preparation method of the CuInS2-In2S3 nanoheterojunction catalyst according to claim 5, characterized in that, In the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst, the reaction temperature is 190-210 ℃.
7. The preparation method of the CuInS2-In2S3 nanoheterojunction catalyst according to claim 5, characterized in that, In the preparation method of the CuInS2-In2S3 nano-heterojunction catalyst, the reaction time is 10-30 min.
8. A CuInS2-In2S3 nano-heterojunction catalyst prepared by the preparation method of any one of claims 5-7.
9. Application of the CuInS2-In2S3 nano-heterojunction catalyst of claim 8 in CO2 reduction.
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In2S3 / CuInS2 thin layer sensitization broadband semiconductor photoanode and preparation method for the same
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