CN113416979B

CN113416979B - Preparation method of AuCu-FeMoS electrocatalyst for nitrogen reduction

Info

Publication number: CN113416979B
Application number: CN202110625845.XA
Authority: CN
Inventors: 常方方; 魏军才; 任梦云; 杨林; 白正宇; 张庆
Original assignee: Henan Normal University
Current assignee: Henan Normal University
Priority date: 2021-06-04
Filing date: 2021-06-04
Publication date: 2023-07-14
Anticipated expiration: 2041-06-04
Also published as: CN113416979A

Abstract

The invention discloses a preparation method of an AuCu-FeMoS electrocatalyst for nitrogen reduction, which comprises the steps of dissolving cuprous chloride and tetrachloro-gold acid hydrate in a mixed solution of hexane and oleylamine, rapidly stirring to form a uniform solution, adding a mixed solution of triisopropylsilane and hexane, and placing the final mixed solution at 60 ℃ until the color becomes black and red to obtain an AuCu alloy nanowire catalyst; dissolving sodium molybdate hydrate and ferric nitrate hydrate in water, adding L-cysteine and high-purity water into the solution, stirring, transferring the solution into a reaction kettle, and reacting to obtain the FeMoS catalyst. And adding the AuCu alloy nanowire catalyst into the FeMoS catalyst standby liquid, stirring and dispersing uniformly, standing at room temperature, sucking out supernatant after the supernatant is clarified, and drying the bottom precipitate in a vacuum drying oven to obtain the electrocatalyst for nitrogen reduction. The synthesis method is simple, the reaction condition is mild, and the prepared product has higher catalytic activity.

Description

Preparation method of AuCu-FeMoS electrocatalyst for nitrogen reduction

Technical Field

The invention belongs to the technical field of nitrogen reduction catalysts, and particularly relates to a preparation method of an AuCu-FeMoS electrocatalyst for nitrogen reduction.

Background

The annual chemical fertilizer consumption is up to 2 hundred million tons worldwide, and ammonia is an important raw material for synthetic fertilizers. The habebosch scheme is the most dominant route in the 20 th century ammonia production industry, but requires high temperature and high pressure conditions, resulting in huge energy consumption and environmental pollution. The electrocatalytic nitrogen reduction is a simple and energy-saving new scheme, so that the synthesis of the catalyst capable of efficiently and selectively catalyzing the nitrogen reduction has important significance.

The alloy catalyst has a high-efficiency and stable composition structure, and theoretical calculation and experimental results show that the AuCu alloy has a great application prospect in the nitrogen reduction field. There is still room for great improvement in terms of yield and product selectivity.

By simulating a natural law, the number of active sites is increased, and the nitrogen conversion rate of the artificial nitrogen fixation enzyme consisting of MoFe or FeV is greatly improved. The FeMoS nitrogen fixation enzyme is combined with the AuCu alloy catalyst, so that the potential can be reduced better, the energy consumption and the environmental pollution can be reduced, and the nitrogen reduction yield and the product selectivity can be improved through the synergistic effect of the FeMoS nitrogen fixation enzyme and the AuCu alloy catalyst.

Disclosure of Invention

The invention solves the technical problem of providing the preparation method of the AuCu-FeMoS electrocatalyst for nitrogen reduction, which has simple synthesis process and mild reaction conditions and can improve the nitrogen reduction yield and the product selectivity.

The invention adopts the following technical scheme to solve the technical problems, and discloses a preparation method of an AuCu-FeMoS electrocatalyst for nitrogen reduction, which is characterized by comprising the following specific steps:

step S1: preparing a mixed solution of hexane and oleylamine with a volume ratio of 1:1, dissolving cuprous chloride and tetrachloro-gold acid hydrate in the mixed solution, rapidly stirring to form a uniform solution, adding a mixed solution of triisopropylsilane and hexane with a volume ratio of 2:5 into the uniform solution at room temperature, and placing the final mixed solution at 60 ℃ until the color becomes black and red to obtain an AuCu alloy nanowire catalyst;

step S2: dissolving sodium molybdate hydrate and ferric nitrate hydrate in water, keeping the pH value of the solution to be 6.5, adding L-cysteine and high-purity water, stirring for 30 minutes to form a uniform transparent solution, transferring into a high-pressure reaction kettle, preserving heat at 200 ℃ for 18 h, cooling to room temperature, centrifugally washing for a plurality of times by absolute ethyl alcohol, and dispersing the obtained FeMoS catalyst in the absolute ethyl alcohol to obtain a standby liquid;

step S3: and (3) adding the AuCu alloy nanowire catalyst obtained in the step (S1) into the standby liquid obtained in the step (S2), stirring and dispersing uniformly, standing at room temperature, sucking out supernatant after the supernatant is clarified, and drying the bottom precipitate in a vacuum drying oven at 45 ℃ to obtain the AuCu-FeMoS electrocatalyst.

Further defined, the charging mass ratio of the cuprous chloride to the tetrachloroauric acid hydrate in the step S1 is 2:15.

Compared with the prior art, the invention has the following beneficial effects:

1. the AuCu-FeMoS electrocatalyst synthesized by the invention has the advantages of simple synthesis method and mild reaction conditions.

2. The AuCu-FeMoS catalyst can better reduce the potential, reduce the energy consumption and the environmental pollution, improve the nitrogen reduction yield and the product selectivity through the synergistic effect of the AuCu-FeMoS catalyst and the AuCu-FeMoS catalyst, and has wide application prospect in the field of nitrogen electrochemical reduction.

Drawings

FIG. 1 is a TEM image of an AuCu alloy nanowire catalyst prepared in the examples;

FIG. 2 is a TEM image of the AuCu-FeMoS electrocatalyst prepared in the examples;

FIG. 3 is a graph comparing ammonia yield and Faraday efficiency of AuCu-FeMoS prepared in the examples with other electrocatalysts.

Detailed Description

The above-described matters of the present invention will be described in further detail by way of examples, but it should not be construed that the scope of the above-described subject matter of the present invention is limited to the following examples, and all techniques realized based on the above-described matters of the present invention are within the scope of the present invention.

Examples

Preparing a mixed solution of 2 mL volume ratio 1:1 hexane and oleylamine, taking 9.88 mg tetrachloroauric acid hydrate and 1.33 mg cuprous chloride in the mixed solution, rapidly stirring to form a uniform solution, adding the 1.4 mL volume ratio 2:5 triisopropylsilane and hexane mixed solution prepared in advance into the uniform solution at room temperature, and standing at 60 ℃ until the solution color turns black and red to obtain the AuCu alloy nanowire catalyst. As can be seen from FIG. 1, the AuCu alloy nano-wire catalyst prepared in the embodiment has better flexibility, the diameter is as small as 1.2 nm, and the length is as long as several micrometers.

Dissolving 0.125 g sodium molybdate hydrate and 0.21 g ferric nitrate hydrate in 20 mL water, keeping the pH value of the solution to be 6.5, adding 0.5 g L-cysteine and 50 mL water, stirring for 30 minutes to form a uniform transparent solution, transferring into a 100 mL high-pressure reaction kettle, preserving heat at 200 ℃ for 18 h, cooling to room temperature, centrifugally washing for a plurality of times by using absolute ethyl alcohol, and dispersing the obtained FeMoS catalyst in the absolute ethyl alcohol to obtain a standby liquid.

Adding an AuCu alloy nanowire catalyst into the standby liquid of the FeMoS catalyst, stirring and dispersing uniformly, standing at room temperature, sucking out supernatant after supernatant is clarified, placing bottom sediment in a vacuum drying oven at 45 ℃, and drying to obtain the AuCu-FeMoS electrocatalyst. From fig. 2, it can be seen that the AuCu-FeMoS electrocatalyst prepared in this example resembles "cotton-ball-shaped" fluffy particles.

2mg of the AuCu-FeMoS electrocatalyst prepared in the embodiment is dispersed in a dispersing agent, the mixed solution is uniformly coated on carbon paper with the size of 1 cm by ultrasonic, a three-electrode H electrolytic cell system is adopted, the performance of the catalyst is measured through an electrochemical workstation, and the yield of ammonia gas as a product is determined by an acid-base neutralization titration method. The ammonia yield and faraday efficiency are shown in figure 3.

The nitrogen reduction electrocatalyst prepared by the invention has good nitrogen reduction yield and product selectivity. In the electrical performance test result of fig. 3, the ammonia yield and faraday efficiency of the AuCu-FeMoS electrocatalyst are optimal, and analysis shows that the AuCu nanowire provides a fluffy porous structure similar to a cotton ball shape for the AuCu-FeMoS electrocatalyst, the FeMoS provides rich nitrogen reduction active sites for the AuCu-FeMoS electrocatalyst, and the synergistic effect of the AuCu-FeMoS electrocatalyst and the FeMoS electrocatalyst increases the electrochemical active surface area, so that the catalytic activity of the catalyst is improved.

While the basic principles, principal features and advantages of the present invention have been described in the foregoing examples, it will be appreciated by those skilled in the art that the present invention is not limited by the foregoing examples, but is merely illustrative of the principles of the invention, and various changes and modifications can be made without departing from the scope of the invention, which is defined by the appended claims.

Claims

1. The preparation method of the AuCu-FeMoS electrocatalyst for nitrogen reduction is characterized by comprising the following specific steps of:

2. The method for preparing the AuCu-FeMoS electrocatalyst for nitrogen reduction according to claim 1, characterized by the specific steps of:

step S1: preparing a mixed solution of 2 mL volume ratio 1:1 hexane and oleylamine, taking 9.88 mg tetrachloroauric acid hydrate and 1.33 mg cuprous chloride in the mixed solution, rapidly stirring to form a uniform solution, adding the 1.4 mL volume ratio 2:5 triisopropylsilane and hexane mixed solution prepared in advance into the uniform solution at room temperature, and standing at 60 ℃ until the solution color turns black and red to obtain an AuCu alloy nanowire catalyst, wherein the AuCu alloy nanowire catalyst has better flexibility, diameter is as small as 1.2 nm and length is in micron order;

step S2: dissolving 0.125 g sodium molybdate hydrate and 0.21 g ferric nitrate hydrate in 20 mL water, keeping the pH value of the solution to be 6.5, adding 0.5 g L-cysteine and 50 mL water, stirring for 30 minutes to form a uniform transparent solution, transferring into a 100 mL high-pressure reaction kettle, preserving heat at 200 ℃ for 18 h, cooling to room temperature, centrifugally washing for a plurality of times by using absolute ethyl alcohol, and dispersing the obtained FeMoS catalyst in the absolute ethyl alcohol to obtain a standby liquid;

step S3: adding an AuCu alloy nanowire catalyst into the standby liquid of the FeMoS catalyst, stirring and dispersing uniformly, standing at room temperature, sucking out supernatant after supernatant is clarified, placing bottom sediment in a vacuum drying oven at 45 ℃, and drying to obtain the AuCu-FeMoS electrocatalyst.