Method for decomposing hydrogen sulfide through electro-catalysis

Abstract

The invention belongs to the field of petrochemical engineering, and particularly relates to a method for decomposing hydrogen sulfide through electro-catalysis. 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 electrocatalytic H2S decomposition process is formed by combining an electrochemical device, and foamed nickel is used as an electrode. 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. According to the process, sulfur and H2 can be obtained through efficient electro-catalysis of hydrogen sulfide under the mild conditions of room temperature, normal pressure and the like.

Description

Technical Field

[0001] The present invention relates to a method for electrocatalytic decomposition of hydrogen sulfide, belonging to the field of petrochemicals. 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 petroleum processing, sulfur compounds are converted to H2S, a chemical that is widely present in raw natural gas. H2S is also a deadly toxic compound. Therefore, proper H2S handling while protecting health and safety is crucial. Common H2S treatment methods include the Claus process to generate sulfur, nitrogen stripping systems, and the use of chemical additives such as alkanolamines and aldehydes to remove H2S from crude oil.

[0003] Electrochemical treatment of pollutants is a sustainable and cost-effective technology with a simpler operating process and the ability to recycle resources under ambient conditions. Although the process can conveniently and efficiently convert H2S into sulfur and H2, it relies on endothermic reactions and requires a lot of energy consumption. In addition, the H2 produced has strict requirements for storage and transportation. The simple electrolysis of H2S will produce the following half-reactions: sulfide oxidation reaction (SOR) occurs at the anode (0.19V) and hydrogen evolution reaction (HER) occurs at the cathode (0.00V). 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 team studied the efficient removal of hydrogen sulfide in a three-dimensional electrochemical catalytic system, investigated the effects of electrolysis conditions, microelectrolysis + electrolysis system, and microelectrolysis + liquid-phase catalytic electrolysis system on the H2S removal rate, and introduced the microelectrolysis effect into the liquid-phase catalytic electrolysis system. Electrochemical technology can desulfurize H2S, but due to system limitations (low mass transfer and catalyst poisoning), the current density is low.

[0004] In the above-mentioned direct electrolytic decomposition of H2S, the transfer of electrons from or to the electrodes is a heterogeneous process that is kinetically hindered, resulting in a high overpotential on the electrode surface. 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. None of the above catalysts have a good solution to the sulfur passivation problem. Since sulfides are directly converted into sulfur, catalyst etching and non-conductive sulfur accumulation on the electrode surface hinder the catalyst's further perception of H2S, resulting in a sharp decline in activity. Therefore, designing an organic solvent (such as CS2) electrolyte with high dissolved sulfur is of great significance for achieving continuous hydrogen production from electrolytic H2S decomposition while stabilizing the electrode through dissolved sulfur accumulation.

[0005] To address current issues such as low mass transfer efficiency, difficult catalyst recovery, sulfur passivation, and cumbersome operating procedures, we provide a method for the electrocatalytic decomposition of H2S into sulfur and H2 using a carbon disulfide-based organic ammonium salt electrolyte as the electrolyte solution. This electrocatalytic hydrogen sulfide decomposition process utilizes a combination of electrochemical devices. Using a carbon disulfide-based organic ammonium salt electrolyte as the electrolyte solution, a one-pot electrocatalytic reaction is performed at room temperature, atmospheric pressure, and 5V for 10 hours, decomposing hydrogen sulfide into sulfur and H2. The sulfur is recovered by rotary evaporation, yielding both H2 and sulfur products. This process efficiently electrocatalyzes hydrogen sulfide to yield sulfur and H2 under mild conditions, such as room temperature and atmospheric pressure. Summary of the Invention

[0006] This invention provides a simple, economical, and recyclable one-pot (room temperature, atmospheric pressure) electrocatalytic decomposition method for H2S into sulfur and H2 in the presence of a carbon disulfide electrolyte solution. This method offers advantages such as ease of operation, high yield, recyclable catalyst, and a non-toxic and pollution-free process.

[0007] The present invention provides a method for preparing H2S by electrocatalytically decomposing it into S and H2 in the presence of a carbon disulfide electrolyte solution, characterized by:

[0008] 1. A method for electrocatalytic decomposition of hydrogen sulfide, comprising the steps of:

[0009] (1) Preparation of 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 electrocatalytically decomposing 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.

[0016] Implementation Effect

[0017] This paper investigates a novel one-pot (room temperature, atmospheric pressure) electrocatalytic decomposition method for H2S into sulfur and H2 in the presence of a carbon disulfide electrolyte solution. This system effectively decomposes H2S into valuable H2 and sulfur. In this system, H2S removal efficiency reaches 99%, and the liquid sulfur product (sulfur dissolved in the CS2-N electrolyte solution, with a yield of up to 95%) is converted into gaseous H2. This work may open up a new electrocatalytic H2S decomposition pathway for the simultaneous production of high-value-added sulfur and H2 using organic electrolyte solutions.

[0018] Claims

[0019] 1. A method for electrocatalytic decomposition of hydrogen sulfide, comprising the following steps: (1) preparing an 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 hexafluorophosphate to an anhydrous methanol solution and stirring for 10 minutes to obtain solution A; adding tetrabutylammonium bromide to an anhydrous ethanol solution and stirring for 10 minutes to obtain solution B; mixing solution B and solution A, stirring for 5 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then adding carbon disulfide to the solution and stirring for 5 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 20 minutes to obtain a carbon disulfide-based electrolyte solution.

[0021] 3. The method according to claim 1, wherein carbon disulfide is used as a base liquid, an organic ammonium salt electrolyte is added to the carbon disulfide, and nickel foam is used as a working electrode (WE) and a counter electrode (CE); the organic ammonium salt electrolyte solution based on carbon disulfide is added to the electrolytic cell, H2S gas is introduced into the electrolytic cell, and hydrogen and sulfur are generated by electrolysis at a certain voltage. 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 hexafluorophosphate to tetrabutylammonium bromide is 0-2:1, and the volume ratio of the alcohol mixed solution of ammonium salt to carbon disulfide is 2-5:3.2. 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, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (0-600 mg) is added to an anhydrous methanol solution (0-25 mL), stirred for 10 minutes to obtain solution A, tetrabutylammonium bromide (0-600 mg) is added to an anhydrous ethanol solution (0-25 mL), stirred for 10 minutes to obtain solution B, solution B and solution A are mixed, stirred for 5 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then carbon disulfide (0-32 mL) is added to the solution and stirred for 5 minutes to fully mix 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 the mixture is stirred for 20 minutes to fully mix to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0027] A method for electrocatalytically decomposing H2S into S and H2 in the presence of a carbon disulfide electrolyte solution comprises the following steps:

[0028] In the electrochemical device, nickel foam (1 cm × 1 cm) served as the working electrode (WE) and counter electrode (CE). A 100 mL sealed glass bottle was charged with a 40 mL carbon disulfide-based organic ammonium salt electrolyte solution at room temperature and pressure. 10% H₂S gas (100 mL / min) was introduced for 1 hour. The electrocatalytic reaction was conducted at room temperature at 400 rpm and a constant voltage of 5 V for 10 hours. Hydrogen production was measured by gas chromatography, yielding 10% to 99%. After the reaction was complete, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. This yielded approximately 30% to 99% H₂S conversion and 24% to 95% sulfur yield.

[0029] The main contents of this method are as follows:

[0030] (1) Selection of carbon disulfide electrolyte ratio:

[0031] First, the choice of the right ratio of different organic ammonium salts and different solutions is crucial. After repeated experiments, we chose a carbon disulfide-based alcohol 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 hexafluorophosphate to tetrabutylammonium bromide, and a 1-5:3.2 volume ratio of the ammonium salt alcohol mixed solution to carbon disulfide.

[0032] (2) Study of reaction conditions:

[0033] 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%.

[0034] Example 1:

[0035] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (300 mg) is added to an anhydrous methanol solution (5 mL), stirred for 10 minutes to obtain solution A, tetrabutylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL), stirred for 10 minutes to obtain solution B, solution B and solution A are mixed, stirred for 5 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then carbon disulfide (32 mL) is added to the solution and stirred for 5 minutes to fully mix 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 the mixture is stirred for 20 minutes to fully mix to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0036] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) 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 with 10% H₂S gas (100 ml / min) for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding an H₂S conversion rate of 99% and a sulfur yield of 95%.

[0037] Example 2:

[0038] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (300 mg) is added to an anhydrous methanol solution (25 mL), stirred for 10 minutes to obtain solution A, tetrabutylammonium bromide (300 mg) is added to an anhydrous ethanol solution (25 mL), stirred for 10 minutes to obtain solution B, solution B and solution A are mixed, stirred for 5 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then carbon disulfide (32 mL) is added to the solution and stirred for 5 minutes to fully mix 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 the mixture is stirred for 20 minutes to fully mix to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0039] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) 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). 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding an 83% H₂S conversion and a 62% sulfur yield.

[0040] Example 3:

[0041] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (300 mg) is added to an anhydrous methanol solution (1 mL), stirred for 10 minutes to obtain solution A, tetrabutylammonium bromide (300 mg) is added to an anhydrous ethanol solution (1 mL), stirred for 10 minutes to obtain solution B, solution B and solution A are mixed, stirred for 5 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then carbon disulfide (32 mL) is added to the solution and stirred for 5 minutes to fully mix 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 the mixture is stirred for 20 minutes to fully mix to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0042] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) 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). 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding a 63% H₂S conversion and a 52% sulfur yield.

[0043] Example 4:

[0044] First, a carbon disulfide-based organic ammonium salt electrolyte solution is prepared: tetrabutylammonium hexafluorophosphate (300 mg) is added to an anhydrous methanol solution (5 mL) and stirred continuously to obtain solution A. Tetrabutylammonium bromide (300 mg) is added to an anhydrous methanol solution (5 mL) and stirred continuously to obtain solution B. Solution B and solution A are mixed and stirred continuously to obtain a methanol-based organic ammonium salt electrolyte solution. Carbon disulfide (32 mL) is then added to the solution and stirred for 5 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte. Dichloromethane is then gradually added dropwise to the solution until the solution becomes clear and transparent. The addition is stopped and stirred for 20 minutes to obtain a carbon disulfide-based organic ammonium salt electrolyte solution.

[0045] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) 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). 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding an 81% H₂S conversion and a 77% sulfur yield.

[0046] Example 5:

[0047] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred continuously to obtain solution A. Tetrabutylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred continuously to obtain solution B. Solution B and solution A are mixed and stirred continuously to obtain an ethanol-based organic ammonium salt electrolyte solution. Carbon disulfide (32 mL) is then added to the solution and stirred for 5 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte. Dichloromethane is then gradually added dropwise to the solution until the solution becomes clear and transparent. The addition is stopped and stirred for 20 minutes to obtain a carbon disulfide-based organic ammonium salt electrolyte solution.

[0048] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) 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). 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding an 83% H₂S conversion and a 75% sulfur yield.

[0049] Example 6:

[0050] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (300 mg) is added to an anhydrous methanol solution (10 mL) and stirred continuously to obtain solution A. Tetrabutylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL) and stirred continuously to obtain solution B. Solution B and solution A are mixed and stirred continuously to obtain an alcohol solution containing an organic ammonium salt electrolyte. Carbon disulfide (32 mL) is then added to the solution and stirred for 5 minutes to obtain a carbon disulfide solution containing an organic ammonium salt electrolyte. Dichloromethane is then gradually added dropwise to the solution until the solution becomes clear and transparent. The addition is stopped and stirred for 20 minutes to obtain a carbon disulfide-based organic ammonium salt electrolyte solution.

[0051] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) 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). 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding a 73% H₂S conversion and a 68% sulfur yield.

[0052] Example 7:

[0053] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (600 mg) is added to an anhydrous methanol solution (5 mL), stirred for 10 minutes to obtain solution A, tetrabutylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL), stirred for 10 minutes to obtain solution B, solution B and solution A are mixed, stirred for 5 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then carbon disulfide (32 mL) is added to the solution and stirred for 5 minutes to fully mix 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 the mixture is stirred for 20 minutes to fully mix to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0054] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) 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). 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding an H₂S conversion of 88% and a sulfur yield of 83%.

[0055] Example 8:

[0056] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium bromide (300 mg) is added to an anhydrous methanol solution (5 mL), stirred for 10 minutes to obtain solution A, tetrabutylammonium bromide (300 mg) is added to an anhydrous ethanol solution (5 mL), stirred for 10 minutes to obtain solution B, solution B and solution A are mixed, stirred for 5 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then carbon disulfide (32 mL) is added to the solution and stirred for 5 minutes to fully mix 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 the mixture is stirred for 20 minutes to fully mix to obtain an organic ammonium salt electrolyte solution based on carbon disulfide.

[0057] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) 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). 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was then separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding an 83% H₂S conversion and a 75% sulfur yield.

[0058] Comparative Example 1:

[0059] First, the electrolyte was prepared: tetrabutylammonium hexafluorophosphate (600 mg) was added to carbon disulfide (50 mL) and stirred for 20 min to obtain the electrolyte.

[0060] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) as the working electrode (WE) and the counter electrode (CE). At room temperature and pressure, an electrolyte (carbon disulfide and tetrabutylammonium hexafluorophosphate alone) (40 mL) was added to a 100 mL sealed glass bottle, and 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator was then removed from the alcohol phase, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding a 15% H₂S conversion and a 12% sulfur yield.

[0061] Comparative Example 2:

[0062] The first step is to prepare the electrolyte: tetrabutylammonium bromide (600 mg) is added to carbon disulfide (50 mL) and stirred for 20 min to obtain the electrolyte.

[0063] The reaction was conducted on an electrochemical workstation, using nickel foam (1 cm × 1 cm) as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, an electrolyte (carbon disulfide and tetrabutylammonium bromide only) (40 mL) was added to a 100 mL sealed glass bottle. 10% H₂S gas (100 mL / min) was then introduced into the reaction flask for 1 hour. The electrocatalytic reaction was conducted at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator was then removed from the alcohol phase, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding an H₂S conversion of approximately 13% and a sulfur yield of 8%.

[0064] Comparative Example 3:

[0065] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (300 mg) is added to an anhydrous ethanol solution (25 mL), and solution A is obtained after continuous stirring. Tetrabutylammonium bromide (300 mg) is added to an anhydrous ethanol solution (25 mL), and solution B is obtained after continuous stirring. Solution B and solution A are mixed, and solution A is obtained after continuous stirring to obtain an ethanol-based organic ammonium salt electrolyte solution.

[0066] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, an ethanol-based organic ammonium salt electrolyte solution (50 mL) was added to a 100 mL sealed glass bottle, and 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte, separating it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, yielding an H₂S conversion rate of 78% and a sulfur yield of 55%.

[0067] Comparative Example 4:

[0068] First, an organic ammonium salt electrolyte solution based on carbon disulfide is prepared: tetrabutylammonium hexafluorophosphate (300 mg) is added to an anhydrous methanol solution (25 mL), and solution A is obtained after continuous stirring. Tetrabutylammonium bromide (300 mg) is added to an anhydrous methanol solution (25 mL), and solution B is obtained after continuous stirring. Solution B and solution A are mixed, and a methanol-based organic ammonium salt electrolyte solution is obtained after continuous stirring.

[0069] The reaction was carried out on an electrochemical workstation, using nickel foam (1 cm × 1 cm) as the working electrode (WE) and counter electrode (CE). At room temperature and pressure, a methanol-based organic ammonium salt electrolyte solution (50 mL) was added to a 100 mL sealed glass bottle, and 10% H₂S gas (100 ml / min) was introduced for 1 hour. The electrocatalytic reaction was carried out at room temperature and 400 rpm under a constant voltage of 5 V for 10 hours. After the reaction was completed, a phase separator was added to the electrolyte to separate it into a carbon disulfide phase and an alcohol phase. The carbon disulfide phase was separated and heated to evaporate to recover the carbon disulfide and sulfur. The phase separator in the alcohol phase was separated, and the electrolyte was recovered for recycling. Hydrogen production was measured by gas chromatography, resulting in an H₂S conversion rate of 81% and a sulfur yield of 60%.

Claims

1. A method for electrocatalytic decomposition of hydrogen sulfide, comprising the steps of: (1) Preparation of 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 hexafluorophosphate is added to an anhydrous methanol solution and stirred for 10 minutes to obtain solution A; tetrabutylammonium bromide is added to an anhydrous ethanol solution and stirred for 10 minutes to obtain solution B; solution B and solution A are mixed and stirred for 5 minutes to obtain an alcohol solution containing an organic ammonium salt electrolyte, and then carbon disulfide is added to the solution and stirred for 5 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 20 minutes to obtain a carbon disulfide-based electrolyte solution.

3. The method according to claim 1, wherein carbon disulfide is used as a base liquid, an organic ammonium salt electrolyte is added to the carbon disulfide, and nickel foam is used as a working electrode (WE) and a counter electrode (CE); an organic ammonium salt electrolyte solution based on carbon disulfide is added to an electrolytic cell, H2S gas is introduced into the electrolytic cell, and hydrogen and sulfur are generated by electrolysis at a certain voltage. 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 hexafluorophosphate to tetrabutylammonium bromide is 0-2:1, and the volume ratio of the alcohol mixed solution of ammonium salt to carbon disulfide is 2-5:3.2.