Preparation method and application of indirect electro-catalysis hydrogen sulfide electrolyte system

Abstract

The invention belongs to the field of petrochemical engineering, and particularly relates to a preparation method and application of an electrolyte for indirectly electro-catalyzing decomposition of hydrogen sulfide. The method is characterized in that a reaction system of an organic ammonium salt electrolyte solution based on carbon disulfide is used for preparing the organic ammonium salt electrolyte solution based on carbon disulfide by blending a plurality of organic ammonium salts and an organic solvent in proportion, an electrochemical device is combined to form an indirect electro-catalysis H2S decomposition process, and cobalt-doped cadmium sulfide (Co-CdSm) is used as a catalyst. The method is characterized in that H2S is subjected to electrocatalysis by adopting a one-pot method under the conditions of room temperature, normal pressure and constant voltage, H2S is decomposed into sulfur and H2, sulfur is recovered through rotary evaporation, and H2 and sulfur products are obtained at the same time. The process can be used for efficiently and indirectly electrocatalyzing hydrogen sulfide to obtain sulfur and H2 under the mild conditions of room temperature, normal pressure and the like.

Description

Technical Field

[0001] This invention relates to a method for preparing and applying an indirect electrocatalytic hydrogen sulfide electrolyte system, belonging to the field of petrochemical engineering. It provides a new catalytic process for decomposing hydrogen sulfide into sulfur and hydrogen using a simple, economical, and recyclable catalyst electrocatalytic operation (at room temperature and atmospheric pressure). The international patent classification is C17 / 16. Technical Background

[0002] During the oil processing process, sulfur compounds are converted into H2S, which is widely present in raw natural gas. At the same time, H2S is a deadly toxic compound. Therefore, it is crucial to properly handle H2S while protecting health and safety. The upper limit for general industries (such as the oil and gas industry, petrochemical industry, metal industry, paper and pulp industry) is 20ppm. Common H2S treatment methods include the Claus process to generate sulfur, nitrogen stripping system, and the use of chemical additives such as alkanolamines and aldehydes to remove H2S from crude oil. H2S is subjected to the Claus process to generate sulfur, and the H in H2S + This process has the problems of high energy and no production of hydrogen (H2). By electrolyzing H2S to produce H2 and sulfur, the effect of molecular economy is achieved.

[0003] Electrochemical treatment of pollutants is a sustainable and cost-effective technology with a simpler operation process and the ability to recycle resources under ambient conditions. The simple electrolysis of H2S will produce the following half-reactions: sulfide oxidation reaction (SOR) at the anode and hydrogen evolution reaction (HER) at the cathode. This method has lower energy consumption, and in addition to H2 (green fuel), the sulfur produced after electrolysis can also be used as the cathode material of sulfur-based batteries, thereby achieving a circular economy. In 2024, Qu's group studied the efficient removal of hydrogen sulfide in a three-dimensional electrochemical catalytic system, and investigated the effects of electrolysis conditions, microelectrolysis + electrolysis system, and microelectrolysis + liquid-phase catalytic electrolysis system on the H2S removal rate. The microelectrolysis effect was introduced into the liquid-phase catalytic electrolysis system, but due to system limitations (low mass transfer and catalyst poisoning), the current density was low, which hindered the electrocatalytic activity. In addition, the elemental sulfur generated in the anodic SOR usually leads to sulfur passivation, hindering the reaction activity and posing a major obstacle to the advancement of electrolytic H2S decomposition. In order to solve the problem of sulfur passivation in direct electrocatalysis, many efficient electrocatalysts have been developed in recent years to promote SOR, including mixed metal oxides (MMOs), carbon-based catalysts, platinum, metal sulfides, and alloy catalysts. However, due to the direct conversion of sulfides to sulfur, catalyst etching and non-conductive sulfur accumulation on the electrode surface hinder the further conversion of H2S by the catalyst, resulting in a sharp decline in catalyst activity.

[0004] In contrast, indirect electrolytic H2S decomposition based on sulfur-soluble organic solvents (such as CS2) is another alternative strategy that can help solve these obstacles. In indirect electrolysis, by preventing the formation of sulfur accumulation on the electrode surface, the overpotential of electron transfer can be avoided and sulfur passivation can be alleviated. Most reported indirect electrolytic H2S decomposition systems are based on homogeneous redox media, which are difficult to recycle or scale up. Therefore, designing an efficient catalyst and organic electrolyte solvent with high conductivity and high solubility of sulfur is of great significance for achieving continuous hydrogen production by indirect electrolytic H2S decomposition while stabilizing the electrode by dissolving sulfur accumulation.

[0005] In order to solve the existing problems of low mass transfer efficiency, difficult catalyst recovery, sulfur passivation, and cumbersome operating procedures, we provide a cobalt-doped cadmium sulfide (Co-CdS) in the presence of an organic ammonium salt electrolyte based on carbon disulfide. m ) is a catalyst for the indirect electrocatalytic decomposition of H2S into sulfur and H2. An indirect electrocatalytic hydrogen sulfide decomposition process is formed by combining electrochemical devices, using an organic ammonium salt electrolyte based on carbon disulfide as the electrolyte solution, Co-CdS m As catalyst, Co-CdS m The ratio of Co to Cd is 1:1. A one-pot electrocatalytic reaction is performed at room temperature, atmospheric pressure, and 3.5V for 5 hours, decomposing hydrogen sulfide into sulfur and H₂. The sulfur is recovered by rotary evaporation, yielding both H₂ and sulfur products. This process enables efficient indirect electrocatalytic conversion of hydrogen sulfide to sulfur and H₂ under mild conditions, such as room temperature and atmospheric pressure. Summary of the Invention

[0006] The purpose of this invention is to provide a simple, economical and recyclable Co-CdS m A new one-pot (room temperature, atmospheric pressure) electrocatalytic decomposition method for H2S into sulfur and H2 has the advantages of being easy to operate, high in yield, recyclable, and non-toxic.

[0007] The solution of the present invention is a Co-CdS m A preparation method for indirectly electrocatalytically decomposing H2S into S and H2 in the presence of a catalyst, characterized by:

[0008] A method for preparing an electrolyte for indirect electrocatalytic decomposition of hydrogen sulfide and its application, comprising the following steps:

[0009] (1) Preparation of carbon disulfide-based electrolyte;

[0010] (2) introducing hydrogen sulfide into the electrolyte;

[0011] (3) electrolyzing an electrolyte containing hydrogen sulfide;

[0012] (4) adding a phase separation agent to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase;

[0013] (5) separating the carbon disulfide phase, heating and evaporating the carbon disulfide, and recovering the sulfur;

[0014] (6) Separate the phase separation agent from the alcohol phase and recover the electrolyte.

[0015] The present invention has unique advantages. The new method for indirect electrocatalytic decomposition of H2S into sulfur and H2 is simple, economical, environmentally friendly, and can be operated by electrocatalysis (at room temperature and pressure). The catalyst is low in price and has a high yield. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 Flow chart for the synthesis of carbon disulfide-based electrolyte solutions. Figure 2 This is a process flow chart for indirect electrocatalytic decomposition of hydrogen sulfide.

[0016] Implementation Effect

[0017] This paper studies a new method for the electrocatalytic decomposition of H2S into sulfur and H2 in the presence of carbon disulfide electrolyte solution in a one-pot method (room temperature, atmospheric pressure). This method can effectively decompose H2S into valuable H2 and sulfur. m As an indirect electrocatalyst, the catalyst exhibited excellent electrocatalytic efficiency, achieving a 99% H2S removal rate and generating gaseous H2 products from liquid sulfur products (sulfur dissolved in a CS2-N electrolyte solution with a yield of up to 95%). This work may open up a new electrocatalytic H2S decomposition pathway for the simultaneous production of high-value-added sulfur and H2 using metallic materials and organic electrolyte solution systems.

[0018] Claims

[0019] 1. A method for preparing an electrolyte for indirect electrocatalytic decomposition of hydrogen sulfide and its application, comprising the following steps: (1) preparing a carbon disulfide-based electrolyte; (2) introducing hydrogen sulfide into the electrolyte; (3) electrolyzing the electrolyte containing hydrogen sulfide; (4) adding a phase separator to the electrolyte to separate the electrolyte into a carbon disulfide phase and an alcohol phase; (5) separating the carbon disulfide phase, heating and evaporating the phase to recover the carbon disulfide and sulfur; and (6) separating the phase separator from the alcohol phase and recovering the electrolyte.

[0020] 2. The method according to claim 1, characterized in that the preparation method of the carbon disulfide-based electrolyte solution comprises the following steps: first, preparing the carbon disulfide-based electrolyte solution, adding tetrabutylammonium tetrafluoroborate to an anhydrous methanol solution and stirring for 5 minutes to obtain solution A; adding tetraethylammonium bromide to an anhydrous ethanol solution and stirring for 5 minutes to obtain solution B; mixing solution B and solution A, stirring for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then adding carbon disulfide to the solution and stirring for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then gradually adding dichloromethane dropwise to the solution until the solution is clear and transparent, stopping the dropwise addition, and then stirring for 10 minutes to obtain a carbon disulfide-based electrolyte solution.

[0021] 3. The method according to claim 1, wherein carbon disulfide is used as the base liquid, an organic ammonium salt electrolyte is added to the carbon disulfide, and nickel foam is used as the working electrode (WE) and the counter electrode (CE); an organic ammonium salt electrolyte solution based on carbon disulfide and Co-CdS are added to the electrolytic cell. m The catalyst is added to the electrolytic cell, H2S gas is introduced into the electrolytic cell, and electrolysis is performed under a certain voltage to produce hydrogen and sulfur. After the reaction is completed, the carbon disulfide solution is distilled to obtain sulfur.

[0022] 4. The method according to claim 1, wherein after the reaction is completed, a phase separator is added to the electrolyte to separate the electrolyte into a carbon disulfide phase and an alcohol phase, the carbon disulfide phase is separated, and the carbon disulfide is recovered by heating and evaporation, and the sulfur is recovered, the phase separator in the alcohol phase is separated, and the electrolyte is recovered.

[0023] 5. The preparation method according to claim 2, characterized in that the volume ratio of methanol to ethanol is 0-2:1, the mass ratio of tetrabutylammonium tetrafluoroborate to tetraethylammonium bromide is 0-2:1, and the volume ratio of the alcohol mixed solution of ammonium salt to carbon disulfide is 0-2:3.2. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the embodiments, but the scope of protection is not limited thereto.

[0025] The preparation method of the organic ammonium salt electrolyte solution based on carbon disulfide comprises the following steps:

[0026] First, a carbon disulfide-based electrolyte solution is prepared. Tetrabutylammonium tetrafluoroborate (300 mg) is added to an anhydrous methanol solution (5 mL) and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide (32 mL) is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte; then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent. After stopping the addition, stir for 10 minutes to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0027] Co-CdS m The preparation method of the catalyst comprises the following steps:

[0028] First, solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6–8 h to obtain Co-CdS m electrocatalyst.

[0029] A Co-CdS electrolyte based on carbon disulfide m A method for preparing a catalyst for indirect electrocatalytic decomposition of H2S into S and H2 comprises the following steps:

[0030] Nickel foam was used as the working electrode (WE) and counter electrode (CE) in the electrochemical device. At room temperature and pressure, a 100 mL sealed glass bottle was added with a carbon disulfide-based organic ammonium salt electrolyte solution (40 mL) and 50 mg Co-CdS m The catalyst is added to a reaction flask and 10% H2S gas (100ml / min) is introduced for 1 hour. The electrocatalytic reaction is carried out at a constant voltage of 3.5V at a rate of 400rpm at room temperature for 5 hours. The hydrogen production is detected by gas chromatography, and the yield is 10% to 99%. After the reaction is completed, a phase separator is added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase is separated, heated and evaporated to recover the carbon disulfide, and the sulfur is recovered. The phase separator in the alcohol phase is separated, and the electrolyte is recovered and recycled. An H2S conversion rate of about 30 to 99% and a sulfur yield of 24 to 95% are obtained.

[0031] The main contents of this method are as follows:

[0032] (1) Selection of carbon disulfide electrolyte ratio:

[0033] First, the choice of the right ratio of organic ammonium salts to different solutions is crucial. After repeated experiments, we chose a carbon disulfide-based alcoholic organic ammonium salt electrolyte solution with the following ratios: a 0-2:1 volume ratio of methanol to ethanol, a 0-2:1 mass ratio of tetrabutylammonium tetrafluoroborate to tetraethylammonium bromide, and a 0-2:3.2 volume ratio of the ammonium salt alcoholic mixed solution to carbon disulfide.

[0034] (2) Study of reaction conditions:

[0035] Improving reaction efficiency, reducing energy waste, and protecting the environment are also key research areas. Therefore, without the use of additional oxidants, an electrocatalytic approach is employed to reduce energy waste, protect the environment, and achieve high yields. Using ambient pressure and temperature, the reaction achieves H2S conversion rates of approximately 5-99% and sulfur yields of 0-95%.

[0036] Example 1:

[0037] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium tetrafluoroborate (300 mg) is added to an anhydrous methanol solution (5 mL) and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide (32 mL) is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent. After stopping the addition, stir for 10 minutes to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0038] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0039] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a carbon disulfide-based organic ammonium salt electrolyte solution (50 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. m The catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and a 99% H2S conversion rate and a 95% sulfur yield were obtained.

[0040] Example 2:

[0041] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium tetrafluoroborate (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide (32 mL) is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent. After stopping the addition, stir for 10 minutes to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0042] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0043] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a carbon disulfide-based organic ammonium salt electrolyte solution (40 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle.m The catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and an H2S conversion rate of 85% and a sulfur yield of 83% were obtained.

[0044] Example 3:

[0045] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium tetrafluoroborate (300 mg) is added to an anhydrous methanol solution (10 mL) and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide (32 mL) is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent. After stopping the addition, stir for 10 minutes to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0046] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0047] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a carbon disulfide-based organic ammonium salt electrolyte solution (40 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. mThe catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and a 95% H2S conversion rate and an 86% sulfur yield were obtained.

[0048] Example 4:

[0049] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetraethylammonium bromide (300 mg) is added to an anhydrous methanol solution (5 mL) and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide (32 mL) is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent. After stopping the addition, stir for 10 minutes to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0050] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0051] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a carbon disulfide-based organic ammonium salt electrolyte solution (40 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. mThe catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide, and the sulfur was recovered. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and an H2S conversion rate of 83% and a sulfur yield of 80% were obtained.

[0052] Example 5:

[0053] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium tetrafluoroborate (600 mg) is added to an anhydrous methanol solution (5 mL) and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide (32 mL) is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent. After stopping the addition, stir for 10 minutes to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0054] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0055] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a carbon disulfide-based organic ammonium salt electrolyte solution (50 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. mThe catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and a 95% H2S conversion rate and an 88% sulfur yield were obtained.

[0056] Example 6:

[0057] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium tetrafluoroborate (300 mg) is added to an anhydrous methanol solution (10 mL) and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide (300 mg) is added to an anhydrous ethanol solution (10 mL) and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide (32 mL) is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent. After stopping the addition, stir for 10 minutes to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0058] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0059] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a carbon disulfide-based organic ammonium salt electrolyte solution (50 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. mThe catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and a 99% H2S conversion rate and a 78% sulfur yield were obtained.

[0060] Example 7:

[0061] First, the electrolyte was prepared: tetrabutylammonium tetrafluoroborate (600 mg) was added to carbon disulfide (32 mL) and stirred for 30 min to obtain electrolyte-A.

[0062] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0063] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and as the counter electrode (CE). At room temperature and pressure, electrolyte-A (carbon disulfide and tetrabutylammonium tetrafluoroborate only) (32 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. m The catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and a 5% H2S conversion rate and a 0% sulfur yield were obtained.

[0064] Example 8:

[0065] First, the electrolyte was prepared: tetraethylammonium bromide (600 mg) was added to carbon disulfide (32 mL) and stirred for 30 min to obtain electrolyte-B.

[0066] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0067] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, electrolyte-B (carbon disulfide and tetraethylammonium bromide only) (32 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. m The catalyst was added to a reaction flask, and 10% H2S gas (100 ml / min) was introduced into the flask for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered for recycling. The hydrogen production was detected by gas chromatography, and an H2S conversion rate of approximately 3% and a sulfur yield of 0% were obtained.

[0068] Example 9:

[0069] The first step is to prepare the electrolyte: add tetrabutylammonium tetrafluoroborate (300 mg) to an anhydrous methanol solution (25 mL) and stir continuously for 10 minutes to obtain solution A; add tetraethylammonium bromide (300 mg) to an anhydrous methanol solution (25 mL) and stir continuously for 10 minutes to obtain solution B; solution B and solution A are mixed and stirred continuously for 30 minutes to obtain a methanol-based organic ammonium salt electrolyte solution.

[0070] Co-CdS mCatalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdS m electrocatalyst.

[0071] The reaction was carried out on an electrochemical workstation, with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a methanol-based organic ammonium salt electrolyte solution (50 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. m The catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and a 79% H2S conversion rate and a 63% sulfur yield were obtained.

[0072] Example 10:

[0073] The first step is to prepare the electrolyte: add tetrabutylammonium tetrafluoroborate (300 mg) to an anhydrous ethanol solution (25 mL) and stir continuously for 10 minutes to obtain solution A; add tetraethylammonium bromide (300 mg) to an anhydrous ethanol solution (25 mL) and stir continuously for 10 minutes to obtain solution B; solution B and solution A are mixed and stirred continuously for 30 minutes to obtain an ethanol-based organic ammonium salt electrolyte solution.

[0074] Co-CdS m Catalyst preparation: Solution A was prepared by placing 123.4 mg of Cd(NO3)2·4H2O and 465.6 mg of Co(NO3)3·6H2O in different molar ratios in 20 mL of deionized water. Solution B containing 1.873 mg (1.2 M) of sodium sulfide (Na2S) was prepared in 20 mL of deionized water. Solution B was added dropwise to solution A to increase the final solution volume to 90 mL. A black precipitate was then formed after hydrothermal treatment at 100 °C for 4 h, washed with a 1:1 mixture of water and ethanol, and then dried at 80 °C for 6-8 h to obtain Co-CdSm electrocatalyst.

[0075] The reaction was carried out on an electrochemical workstation with nickel foam as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, an ethanol-based organic ammonium salt electrolyte solution (50 mL) and 50 mg Co-CdS were added to a 100 mL sealed glass bottle. m The catalyst was added to a reaction flask and 10% H2S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5V at a rate of 400 rpm at room temperature for 5 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered and recycled. The hydrogen production was detected by gas chromatography, and an H2S conversion rate of 81% and a sulfur yield of 58% were obtained.

[0076] Comparative Example 1:

[0077] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium tetrafluoroborate (300 mg) is added to an anhydrous methanol solution (5 mL) and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide (32 mL) is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent. After stopping the addition, stir for 10 minutes to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0078] The reaction was carried out on an electrochemical workstation, with nickel foam serving as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a 100 mL sealed glass bottle was filled with a carbon disulfide-based organic ammonium salt electrolyte solution (40 mL) and introduced into the reaction flask. 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at a constant voltage of 3.5 V at a rate of 400 rpm for 5 hours without a catalyst. After the reaction was complete, a phase separator was added to the electrolyte to separate the carbon disulfide phase and the alcohol phase. The carbon disulfide phase was separated, heated and evaporated to recover the carbon disulfide, and sulfur was recovered. The phase separator in the alcohol phase was separated, and the electrolyte was recovered for recycling. The hydrogen production was detected by gas chromatography, yielding an H₂S conversion of approximately 35% and a sulfur yield of 29%.

Claims

1. A method for preparing an electrolyte for indirect electrocatalytic decomposition of hydrogen sulfide and its application, comprising the following steps: (1) Preparation of carbon disulfide-based electrolyte; (2) introducing hydrogen sulfide into the electrolyte; (3) electrolyzing an electrolyte containing hydrogen sulfide; (4) adding a phase separator to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase; (5) separating the carbon disulfide phase, heating and evaporating it to recover the carbon disulfide and sulfur; (6) separating the phase separator from the alcohol phase and recovering the electrolyte.

2. The method according to claim 1, characterized in that The steps of the preparation method of the carbon disulfide-based electrolyte solution are as follows: first, the carbon disulfide-based electrolyte solution is prepared, tetrabutylammonium tetrafluoroborate is added to an anhydrous methanol solution and stirred for 5 minutes to obtain solution A; tetraethylammonium bromide is added to an anhydrous ethanol solution and stirred for 5 minutes to obtain solution B; solution B and solution A are mixed and stirred for 10 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte; then carbon disulfide is added to the solution and stirred for 20 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte, and then dichloromethane is gradually added dropwise to the solution until the solution is clear and transparent, the addition is stopped, and then stirred for 10 minutes to obtain a carbon disulfide-based electrolyte solution.

3. The method according to claim 1, wherein carbon disulfide is used as the base liquid, an organic ammonium salt electrolyte is added to the carbon disulfide, and nickel foam is used as the working electrode (WE) and the counter electrode (CE); an organic ammonium salt electrolyte solution based on carbon disulfide and Co-CdS are added to the electrolytic cell; m The catalyst is added to the electrolytic cell, H2S gas is introduced into the electrolytic cell, and electrolysis is performed under a certain voltage to produce hydrogen and sulfur. After the reaction is completed, the carbon disulfide solution is distilled to obtain sulfur.

4. The method according to claim 1, wherein after the reaction is completed, a phase separator is added to the electrolyte to separate the electrolyte into a carbon disulfide phase and an alcohol phase, the carbon disulfide phase is separated, the carbon disulfide is recovered by heating and evaporation, and the sulfur is recovered, the phase separator in the alcohol phase is separated, and the electrolyte is recovered.

5. The preparation method according to claim 2, characterized in that The volume ratio of methanol to ethanol is 0-2:1, the mass ratio of tetrabutylammonium tetrafluoroborate to tetraethylammonium bromide is 0-2:1, and the volume ratio of the alcohol mixed solution of ammonium salt to carbon disulfide is 0-2:3.2.

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