Tin sulfide / bismuth sulfide composite material and preparation method and application thereof

Abstract

The invention belongs to the technical field of electrocatalytic carbon dioxide reduction, and discloses a tin sulfide / bismuth sulfide composite material and a preparation method and application thereof. The preparation method comprises the following steps: mixing a tin source, a bismuth source, a sulfur source, an active agent, an acid solution and a solvent to obtain a mixed solution; and performing solvothermal reaction on the mixed solution, and drying to obtain the tin sulfide / bismuth sulfide composite material. The tin sulfide / bismuth sulfide composite material is synthesized by adopting a simple solvothermal method and a one-pot method, and under the action of an active agent, not only are active sites of tin sulfide increased, but also the microstructure of bismuth sulfide is regulated and controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocatalytic carbon dioxide reduction, and in particular to a tin sulfide / bismuth sulfide composite material and a preparation method and application thereof. Background Art

[0002] Since the Industrial Revolution, the rapid growth of the global population and the increasing demand for fossil fuels have led to a sharp increase in the concentration of carbon dioxide (CO2) in the atmosphere, resulting in a series of global climate and environmental problems such as glacier melting, sea level rise, ocean acidification and excessive drought. Therefore, exploring ways to reduce CO2 emissions is a major task facing today's society. So far, the conversion of CO2 can be achieved through chemical conversion methods such as photochemistry, biochemistry and electrochemistry. Among them, electrocatalytic CO2 reduction can obtain electrical energy through renewable energy such as solar energy and wind energy, and then catalyze CO2 reduction. Due to the advantages of mild conditions, controllability and high efficiency of electrocatalytic reactions, electrocatalytic CO2 reduction has a high application prospect. The hydrogen evolution side reaction occurs at the cathode of the cathode chamber and is an inevitable competitive reaction in the electrocatalytic CO2 reduction process. Due to the stable molecular structure of CO2, the design of highly selective, energy-efficient and low-cost electrocatalysts is the key.

[0003] However, electrocatalytic CO2 reduction technology faces a series of problems and challenges: First, CO2 has a molecular structure with stable thermodynamic properties, and the dissociation process of its C=O double bond needs to overcome a relatively high energy barrier; second, in the process of CO2 electrocatalytic reduction, multi-proton coupling and electron transfer processes usually generate a large number of intermediates, resulting in low product selectivity; finally, in aqueous electrolytes, the occurrence of hydrogen evolution side reactions is inevitable, which also reduces the selectivity of electrocatalytic CO2 reduction. The electrocatalytic CO2 reduction reaction can form a variety of products, including carbon monoxide, methane, formic acid / formate, methanol, ethylene, ethane, ethanol, n-propanol, etc. Among them, formic acid / formate is an important hydrogen storage medium that can be used directly as a battery fuel or converted into CO, H2 and methanol. Due to the high market value and relatively low energy input of formic acid / formate, it is promising to study the electrocatalytic reduction of CO2 to formic acid / formate.

[0004] As an important class of semiconductor materials, tin sulfide (SnS2) and bismuth sulfide (Bi2S3) have shown great potential in the field of electrocatalytic CO2 reduction. SnS2 is a layered semiconductor material with good electrical conductivity and stability. It has a wide range of applications in optoelectronic devices, microelectronic devices, biosensors, chemical sensors, and electrocatalytic CO2 reduction. Through intercalation modification, its electronic structure and chemical properties can be regulated to improve its electrocatalytic performance. As a narrow bandgap semiconductor, Bi2S3 has excellent photoelectric properties and high electrocatalytic activity. Its electrocatalytic performance can be further improved by improving its structural properties. Sn-based compounds and Bi-based compounds are both very promising catalysts for electrocatalytic CO2 reduction. However, the electrocatalytic CO2 reduction of pure SnS2 and Bi2S3 is accompanied by a strong hydrogen evolution side reaction, which greatly inhibits the electrocatalytic CO2 reduction performance.

[0005] Therefore, it is of great significance to study and obtain a tin sulfide / bismuth sulfide composite material with high activity and fewer side reactions and a preparation method thereof. Summary of the invention

[0006] In view of this, the present invention provides a tin sulfide / bismuth sulfide composite material and a preparation method and application thereof, the purpose of which is to solve the problems of more side reactions and poor reduction performance of existing composite materials during electrocatalytic CO2 reduction.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The present invention provides a tin sulfide / bismuth sulfide composite material, in which the molar ratio of tin element to bismuth element is 0.001-1000:1.

[0009] The present invention also provides a method for preparing a tin sulfide / bismuth sulfide composite material, comprising the following steps:

[0010] 1) mixing a tin source, a bismuth source, a sulfur source, an activator, an acid solution and a solvent to obtain a mixed solution;

[0011] 2) subjecting the mixed solution to a solvent thermal reaction and then drying to obtain a tin sulfide / bismuth sulfide composite material.

[0012] Preferably, in step 1), the tin source comprises one or more of stannous fluoride, stannous chloride, stannous bromide, stannous iodide, stannous oxide, stannous sulfate, stannous nitrate, stannous acetate, stannous oxalate, tin pyrophosphate, tin fluoride, tin chloride, tin bromide, tin iodide, tin oxide, tin sulfate, tin nitrate and tin acetate;

[0013] The bismuth source includes one or more of bismuth nitrate, bismuth subnitrate, bismuth sulfate, bismuth acetate, bismuth phosphate, bismuth citrate, ammonium bismuth citrate, bismuth subcarbonate, bismuth subsalicylate, potassium bismuth citrate, bismuth chloride, bismuth bromide and bismuth oxide.

[0014] Preferably, in step 1), the sulfur source includes one or more of lithium sulfide, sodium sulfide, potassium sulfide, thioacetamide, thiourea, L-cysteine ​​and carbon disulfide;

[0015] The active agent includes one or more of ethylenediamine, diethylenetriamine, hexadecylamine, octadecylamine, hexadecyltrimethylammonium bromide, dodecanethiol, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, dioctyl sodium sulfosuccinate, sodium iminodisuccinate, polyvinylpyrrolidone, polyethyleneimine and polyethylene glycol.

[0016] Preferably, in step 1), the solvent of the acid solution is water, the acid solution is hydrochloric acid, sulfuric acid, nitric acid, formic acid solution or acetic acid solution, and the concentration of the acid solution is 0.01 to 5 mol / L;

[0017] The solvent in step 1) includes one or more of water, methanol, anhydrous ethanol, n-propanol, isopropanol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerol, n-butanol and 2-butanol.

[0018] Preferably, in the step 1), the ratio of the sum of the amount of bismuth in the bismuth source and the amount of tin in the tin source to the amount of sulfur in the sulfur source is 1:5-50;

[0019] The molar ratio of the tin element in the tin source to the bismuth element in the bismuth source is 0.001 to 1000:1.

[0020] Preferably, in step 1), the usage ratio of sulfur element in the sulfur source, activator, acid solution and solvent is 0.01-0.5 mol: 0.01-30 g: 1-100 mL: 50-300 mL.

[0021] Preferably, in step 2), the temperature of the solvent thermal reaction is 150-210° C. and the time is 4-24 hours.

[0022] Preferably, in step 2), the drying temperature is 50-70° C. and the drying time is 4-10 hours.

[0023] The present invention also provides an application of the tin sulfide / bismuth sulfide composite material in the field of electrocatalytic CO2 reduction.

[0024] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention realizes the intercalation of tin sulfide and the morphology control of bismuth sulfide, and combines the two to form a heterojunction structure. The combination of tin sulfide and bismuth sulfide increases the specific surface area of ​​the electrocatalyst, increases the active sites, and further improves the electrocatalytic carbon dioxide performance of the composite material.

[0026] The present invention adopts a simple solvent thermal method to synthesize the tin sulfide / bismuth sulfide composite material through a one-pot method. Under the action of an activating agent, the active sites of tin sulfide are increased and the microscopic morphology of bismuth sulfide is regulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 is the XRD pattern of the tin sulfide / bismuth sulfide composite material obtained in Example 3;

[0029] Figure 2 is a SEM image of the tin sulfide / bismuth sulfide composite material obtained in Example 3;

[0030] Figure 3 Elemental analysis diagram of the tin sulfide / bismuth sulfide composite material obtained in Example 3;

[0031] Figure 4 This is a graph showing the electro-reduction catalytic performance of the tin sulfide / bismuth sulfide composite material obtained in Example 3 at different voltages;

[0032] Figure 5 This is a SEM image of the tin sulfide electrocatalytic material obtained in Comparative Example 1;

[0033] Figure 6 This is a SEM image of the bismuth sulfide electrocatalytic material obtained in Comparative Example 2;

[0034] Figure 7 This is a SEM image of the tin sulfide electrocatalytic material obtained in Comparative Example 3;

[0035] Figure 8 This is the SEM image of the bismuth sulfide electrocatalytic material obtained in Comparative Example 4. DETAILED DESCRIPTION

[0036] The present invention provides a tin sulfide / bismuth sulfide composite material, in which the molar ratio of tin element to bismuth element is 0.001-1000:1.

[0037] In the present invention, the molar ratio of the tin element to the bismuth element is preferably 0.05 to 500:1, more preferably 0.5 to 2:1, and even more preferably 1 to 1.5:1.

[0038] In the present invention, the tin sulfide / bismuth sulfide composite material is rod-shaped bismuth sulfide wrapped by flake tin sulfide.

[0039] The present invention also provides a method for preparing a tin sulfide / bismuth sulfide composite material, comprising the following steps:

[0040] 1) mixing a tin source, a bismuth source, a sulfur source, an activator, an acid solution and a solvent to obtain a mixed solution;

[0041] 2) subjecting the mixed solution to a solvent thermal reaction and then drying to obtain a tin sulfide / bismuth sulfide composite material.

[0042] In the present invention, in the step 1), the tin source preferably includes one or more of stannous fluoride, stannous chloride, stannous bromide, stannous iodide, stannous oxide, stannous sulfate, stannous nitrate, stannous acetate, stannous oxalate, tin pyrophosphate, tin fluoride, tin chloride, tin bromide, tin iodide, tin oxide, tin sulfate, tin nitrate and tin acetate;

[0043] The bismuth source preferably includes one or more of bismuth nitrate, bismuth subnitrate, bismuth sulfate, bismuth acetate, bismuth phosphate, bismuth citrate, ammonium bismuth citrate, bismuth subcarbonate, bismuth subsalicylate, potassium bismuth citrate, bismuth chloride, bismuth bromide and bismuth oxide.

[0044] In the present invention, in step 1), the sulfur source preferably includes one or more of lithium sulfide, sodium sulfide, potassium sulfide, thioacetamide, thiourea, L-cysteine ​​and carbon disulfide;

[0045] The active agent preferably includes one or more of ethylenediamine, diethylenetriamine, hexadecylamine, octadecylamine, hexadecyltrimethylammonium bromide, dodecanethiol, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, dioctyl sodium sulfosuccinate, sodium iminodisuccinate, polyvinylpyrrolidone, polyethyleneimine and polyethylene glycol.

[0046] In the present invention, in the step 1), the solvent of the acid solution is preferably water, the acid solution is preferably hydrochloric acid, sulfuric acid, nitric acid, formic acid solution or acetic acid solution, and the concentration of the acid solution is preferably 0.01 to 5 mol / L, more preferably 0.1 to 3 mol / L, and more preferably 1 to 2 mol / L;

[0047] In the step 1), the solvent preferably includes one or more of water, methanol, anhydrous ethanol, n-propanol, isopropanol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerol, n-butanol and 2-butanol.

[0048] In the present invention, in the step 1), the ratio of the sum of the amount of bismuth in the bismuth source and the amount of tin in the tin source to the amount of sulfur in the sulfur source is preferably 1:5 to 50, more preferably 1:10 to 40, and more preferably 1:20 to 30;

[0049] The molar ratio of the tin element in the tin source to the bismuth element in the bismuth source is preferably 0.001 to 1000:1, more preferably 0.05 to 500:1, and even more preferably 0.5 to 2:1.

[0050] In the present invention, in the step 1), the usage ratio of sulfur element, activator, acid solution and solvent in the sulfur source is preferably 0.01-0.5 mol: 0.01-30 g: 1-100 mL: 50-300 mL, more preferably 0.05-0.3 mol: 5-25 g: 10-80 mL: 100-250 mL, and more preferably 0.1-0.2 mol: 10-20 g: 25-50 mL: 150-200 mL.

[0051] In the present invention, in the step 1), the mixing is preferably magnetic stirring, and the speed of the magnetic stirring is preferably 400-800 rpm, more preferably 500-700 rpm, and more preferably 550-600 rpm; the time of the magnetic stirring is preferably 50-70 min, more preferably 55-65 min, and more preferably 60-62 min.

[0052] In the present invention, in step 2), the temperature of the solvothermal reaction is preferably 150-210°C, more preferably 160-200°C, more preferably 170-180°C, and the time is preferably 4-24h, more preferably 8-20h, more preferably 12-16h.

[0053] In the present invention, in the step 2), after the solvent thermal reaction, cooling, primary centrifugation, washing and secondary centrifugation are preferably performed in sequence to obtain a solid product; wherein the cooling temperature is preferably 20-30°C, more preferably 22-28°C, and more preferably 25-26°C, the purpose of the primary centrifugation and the secondary centrifugation is to separate the solid and the liquid, the rotation speed of the primary centrifugation and the secondary centrifugation is independently preferably 5000-10000rpm, more preferably 6000-9000rpm, and more preferably 7000-8000rpm, the solid obtained by the primary centrifugation is washed, and the washing reagents are preferably water and anhydrous ethanol in sequence, and the number of water washings and the number of anhydrous ethanol washings are independently preferably 1-5 times, more preferably 2-4 times, and more preferably 3 times.

[0054] In the present invention, in the step 2), the solvent thermal reaction is preferably carried out in a polytetrafluoroethylene liner, and more preferably the polytetrafluoroethylene liner is placed in a blast dryer for the reaction.

[0055] In the present invention, in the step 2), the drying temperature is preferably 50-70°C, more preferably 55-65°C, more preferably 60-62°C, and the drying time is preferably 4-10h, more preferably 5-8h, more preferably 6-7h; the drying is preferably vacuum drying, and the vacuum degree of vacuum drying is preferably 0-0.2kPa, more preferably 0.08-0.18kPa, more preferably 0.1-0.12kPa.

[0056] The present invention also provides an application of the tin sulfide / bismuth sulfide composite material in the field of electrocatalytic CO2 reduction.

[0057] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0058] In the embodiments and comparative examples of the present invention, the solvent thermal reaction is carried out in a polytetrafluoroethylene liner placed in a blast drying oven.

[0059] Example 1

[0060] 0.23 g of stannous chloride dihydrate, 14.12 g of bismuth sulfate, 9.65 g of lithium sulfide, 0.01 g of diethylenetriamine, 1 mL of sulfuric acid (concentration of 0.01 mol / L) and 50 mL of deionized water were magnetically stirred at a speed of 600 rpm for 60 min to obtain a mixed solution (wherein the molar ratio of Sn to Bi is 0.05:1);

[0061] The mixed solution was heated at 150°C for 4 hours. After the reaction was completed, it was naturally cooled to 25°C, and the cooled product was centrifuged at a speed of 8000 rpm. The solid obtained by centrifugation was washed three times with deionized water, and then washed three times with anhydrous ethanol, and then centrifuged again at a speed of 8000 rpm to obtain a solid product;

[0062] The obtained solid product was vacuum dried at 60° C. under a vacuum degree of 0.1 kPa for 10 h to obtain a tin sulfide / bismuth sulfide composite material.

[0063] Example 2

[0064] 0.22 g of stannous sulfate, 0.77 g of bismuth acetate, 3.6 g of sodium sulfide nonahydrate, 0.1 g of dodecanethiol, 5 mL of nitric acid (concentration of 0.1 mol / L) and 100 mL of methanol were magnetically stirred at 600 rpm for 60 min to obtain a mixed solution (wherein the molar ratio of Sn to Bi was 0.5:1);

[0065] The mixed solution was heated at 165°C for 9 hours. After the reaction was completed, it was naturally cooled to 25°C, and the cooled product was centrifuged at a speed of 9000 rpm. The solid obtained by centrifugation was washed three times with deionized water, and then washed three times with anhydrous ethanol, and then centrifuged again at a speed of 9000 rpm to obtain a solid product;

[0066] The obtained solid product was vacuum dried at 60° C. under a vacuum degree of 0.1 kPa for 10 h to obtain a tin sulfide / bismuth sulfide composite material.

[0067] Example 3

[0068] 0.53 g of tin tetrachloride pentahydrate, 0.73 g of bismuth nitrate pentahydrate, 1.50 g of thiourea, 0.50 g of hexadecyltrimethylammonium bromide, 10 mL of hydrochloric acid (concentration of 1 mol / L) and 150 mL of anhydrous ethanol were magnetically stirred at a speed of 600 rpm for 60 min to obtain a mixed solution (wherein the molar ratio of Sn to Bi is 1:1);

[0069] The mixed solution was heated at 180°C for 14 hours. After the reaction was completed, it was naturally cooled to 25°C, and the cooled product was centrifuged at a speed of 10,000 rpm. The solid obtained by centrifugation was washed three times with deionized water, and then washed three times with anhydrous ethanol, and then centrifuged again at a speed of 10,000 rpm to obtain a solid product;

[0070] The obtained solid product was vacuum dried at 60° C. under a vacuum degree of 0.1 kPa for 8 h to obtain a tin sulfide / bismuth sulfide composite material.

[0071] Example 4

[0072] 1.25 g of tin iodide, 0.40 g of bismuth citrate, 6.76 g of thioacetamide, 5 g of sodium dodecylbenzenesulfonate, 50 mL of formic acid solution (the solvent is water, the concentration is 2.5 mol / L) and 200 mL of ethylene glycol are magnetically stirred at a speed of 600 rpm for 60 min to obtain a mixed solution (wherein the molar ratio of Sn to Bi is 2:1);

[0073] The mixed solution was heated at 195°C for 19h. After the reaction was completed, it was naturally cooled to 25°C, and the cooled product was centrifuged at a speed of 6000rpm. The solid obtained by centrifugation was washed three times with deionized water, and then washed three times with anhydrous ethanol, and then centrifuged again at a speed of 6000rpm to obtain a solid product;

[0074] The obtained solid product was vacuum dried at 60° C. under a vacuum degree of 0.1 kPa for 10 h to obtain a tin sulfide / bismuth sulfide composite material.

[0075] Example 5

[0076] 4.13 g of stannous oxalate, 0.45 g of bismuth bromide, 60 g of L-cysteine, 30 g of polyvinyl pyrrolidone, 100 mL of acetic acid solution (the solvent is water, the concentration is 5 mol / L) and 300 mL of glycerol are magnetically stirred at a speed of 600 rpm for 60 min to obtain a mixed solution (wherein the molar ratio of Sn to Bi is 20:1);

[0077] The mixed solution was heated at 210°C for 24 hours. After the reaction was completed, it was naturally cooled to 25°C, and the cooled product was centrifuged at a speed of 7000 rpm. The solid obtained by centrifugation was washed three times with deionized water, and then washed three times with anhydrous ethanol, and then centrifuged again at a speed of 7000 rpm to obtain a solid product;

[0078] The obtained solid product was vacuum dried at 60° C. under a vacuum degree of 0.1 kPa for 10 h to obtain a tin sulfide / bismuth sulfide composite material.

[0079] Comparative Example 1

[0080] 0.53 g of tin tetrachloride pentahydrate, 1.50 g of thiourea, 10 mL of hydrochloric acid (concentration: 1 mol / L) and 100 mL of deionized water were magnetically stirred at 600 rpm for 60 min to obtain a mixed solution;

[0081] The mixed solution was heated at 180°C for 16 hours. After the reaction was completed, it was naturally cooled to 25°C, and the cooled product was centrifuged at a speed of 10,000 rpm. The solid obtained by centrifugation was washed three times with deionized water, and then washed three times with anhydrous ethanol, and then centrifuged again at a speed of 10,000 rpm to obtain a solid product;

[0082] The obtained solid product was vacuum dried at 60° C. under a vacuum degree of 0.1 kPa for 10 h to obtain a tin sulfide electrocatalytic material.

[0083] Comparative Example 2

[0084] 0.73 g of bismuth nitrate pentahydrate, 1.50 g of thiourea, 10 mL of hydrochloric acid (concentration of 1 mol / L) and 100 mL of deionized water were magnetically stirred at a speed of 600 rpm for 60 min to obtain a mixed solution;

[0085] The mixed solution was heated at 180°C for 16 hours. After the reaction was completed, it was naturally cooled to 25°C, and the cooled product was centrifuged at a speed of 10,000 rpm. The solid obtained by centrifugation was washed three times with deionized water, and then washed three times with anhydrous ethanol, and then centrifuged again at a speed of 10,000 rpm to obtain a solid product;

[0086] The obtained solid product was vacuum dried at 60° C. under a vacuum degree of 0.1 kPa for 10 h to obtain a bismuth sulfide electrocatalytic material.

[0087] Comparative Example 3

[0088] The steps in Comparative Example 1 are as follows: “0.53 g of tin tetrachloride pentahydrate, 1.50 g of thiourea, 10 mL of hydrochloric acid (concentration of 1 mol / L) and 100 mL of deionized water are magnetically stirred at 600 rpm for 60 min to obtain a mixed solution” is replaced with “0.53 g of tin tetrachloride pentahydrate, 1.50 g of thiourea, 10 mL of hydrochloric acid (concentration of 1 mol / L), 0.50 g of hexadecyltrimethylammonium bromide and 100 mL of deionized water are magnetically stirred at 600 rpm for 60 min to obtain a mixed solution”. The other steps are the same as those in Comparative Example 1.

[0089] Comparative Example 4

[0090] The steps in Comparative Example 2 are replaced by “0.73 g of bismuth nitrate pentahydrate, 1.50 g of thiourea, 10 mL of hydrochloric acid (concentration of 1 mol / L) and 100 mL of deionized water, and the mixture is magnetically stirred at 600 rpm for 60 min to obtain a mixed solution” with “0.73 g of bismuth nitrate pentahydrate, 1.50 g of thiourea, 10 mL of hydrochloric acid (concentration of 1 mol / L), 0.50 g of hexadecyltrimethylammonium bromide and 100 mL of deionized water, and the mixture is magnetically stirred at 600 rpm for 60 min to obtain a mixed solution”, and the other steps are the same as those in Comparative Example 2.

[0091] The tin sulfide / bismuth sulfide composite materials obtained in Examples 1 to 5, the tin sulfide electrocatalytic material obtained in Comparative Example 1, and the bismuth sulfide electrocatalytic material obtained in Comparative Example 2 were respectively used as electrocatalytic materials for electrocatalytic reduction of carbon dioxide to formate, and the specific steps were as follows:

[0092] In an electrolytic cell separated into an anode tank and a cathode tank by a proton exchange membrane, an electrocatalytic material is used as a working electrode (cathode), a platinum sheet is used as a counter electrode (anode), and a saturated calomel electrode is used as a reference electrode (cathode). A 0.1 mol / L KHCO3 electrolyte solution is respectively loaded in the anode tank and the cathode tank. CO2 is introduced into the cathode tank to a saturated state, and then CO2 is reduced at a constant potential under the condition of continuous introduction of CO2. The potential control range of the constant potential reduction process is -1.2 to -2.0 V (vs. RHE), and the Faraday efficiency of electrocatalytic CO2 reduction to formate is measured at a constant voltage of -1.1 V (vs. RHE). The measurement results are shown in Table 1.

[0093] Table 1 Faraday efficiency test results of the electrocatalytic CO2 reduction to formate of the products obtained in Examples 1 to 5 and Comparative Examples 1 to 2

[0094]

[0095] As can be seen from Table 1, the Faraday efficiency of the electrocatalytic CO2 reduction to formate of the tin sulfide / bismuth sulfide composite materials obtained in Examples 1 to 5 is greater than 82%, while that of the tin sulfide electrocatalytic material obtained in Comparative Example 1 and the bismuth sulfide electrocatalytic material obtained in Comparative Example 2 is 74.60% and 69.20%. It can be seen that the tin sulfide / bismuth sulfide composite material obtained in the present invention has good catalytic stability.

[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A tin sulfide / bismuth sulfide composite material, characterized in that: In the tin sulfide / bismuth sulfide composite material, the molar ratio of tin element to bismuth element is 0.001-1000:

1.

2. The method for preparing the tin sulfide / bismuth sulfide composite material according to claim 1, characterized in that: The steps include: 1) mixing a tin source, a bismuth source, a sulfur source, an activator, an acid solution and a solvent to obtain a mixed solution; 2) subjecting the mixed solution to a solvent thermal reaction and then drying to obtain a tin sulfide / bismuth sulfide composite material.

3. The method for preparing a tin sulfide / bismuth sulfide composite material according to claim 2, characterized in that: In the step 1), the tin source includes one or more of stannous fluoride, stannous chloride, stannous bromide, stannous iodide, stannous oxide, stannous sulfate, stannous nitrate, stannous acetate, stannous oxalate, tin pyrophosphate, tin fluoride, tin chloride, tin bromide, tin iodide, tin oxide, tin sulfate, tin nitrate and tin acetate; The bismuth source includes one or more of bismuth nitrate, bismuth subnitrate, bismuth sulfate, bismuth acetate, bismuth phosphate, bismuth citrate, ammonium bismuth citrate, bismuth subcarbonate, bismuth subsalicylate, potassium bismuth citrate, bismuth chloride, bismuth bromide and bismuth oxide.

4. A method for preparing a tin sulfide / bismuth sulfide composite material according to claim 2 or 3, characterized in that: In the step 1), the sulfur source includes one or more of lithium sulfide, sodium sulfide, potassium sulfide, thioacetamide, thiourea, L-cysteine ​​and carbon disulfide; The active agent includes one or more of ethylenediamine, diethylenetriamine, hexadecylamine, octadecylamine, hexadecyltrimethylammonium bromide, dodecanethiol, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, dioctyl sodium sulfosuccinate, sodium iminodisuccinate, polyvinylpyrrolidone, polyethyleneimine and polyethylene glycol.

5. The method for preparing a tin sulfide / bismuth sulfide composite material according to claim 4, characterized in that: In the step 1), the solvent of the acid solution is water, the acid solution is hydrochloric acid, sulfuric acid, nitric acid, formic acid solution or acetic acid solution, and the concentration of the acid solution is 0.01 to 5 mol / L; The solvent in step 1) includes one or more of water, methanol, anhydrous ethanol, n-propanol, isopropanol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerol, n-butanol and 2-butanol.

6. The method for preparing a tin sulfide / bismuth sulfide composite material according to claim 5, characterized in that: In the step 1), the ratio of the sum of the amount of bismuth in the bismuth source and the amount of tin in the tin source to the amount of sulfur in the sulfur source is 1:5-50; The molar ratio of the tin element in the tin source to the bismuth element in the bismuth source is 0.001 to 1000:

1.

7. A method for preparing a tin sulfide / bismuth sulfide composite material according to claim 5 or 6, characterized in that: In the step 1), the usage ratio of sulfur element in the sulfur source, the activating agent, the acid solution and the solvent is 0.01-0.5 mol: 0.01-30 g: 1-100 mL: 50-300 mL.

8. The method for preparing a tin sulfide / bismuth sulfide composite material according to claim 7, characterized in that: In the step 2), the temperature of the solvent thermal reaction is 150 to 210° C. and the time is 4 to 24 hours.

9. The method for preparing a tin sulfide / bismuth sulfide composite material according to claim 8, characterized in that: In the step 2), the drying temperature is 50 to 70° C. and the drying time is 4 to 10 hours.

10. Use of the tin sulfide / bismuth sulfide composite material according to claim 1 in the field of electrocatalytic CO2 reduction.

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