阅读说明：本技术 一种用于氮气还原的AuCu-FeMoS电催化剂的制备方法 (Preparation method of AuCu-FeMoS electrocatalyst for nitrogen reduction ) 是由 常方方 魏军才 任梦云 杨林 白正宇 张庆 于 2021-06-04 设计创作，主要内容包括：本发明公开了一种用于氮气还原的AuCu-FeMoS电催化剂的制备方法,将氯化亚铜和四氯金酸水合物溶解于己烷与油胺混合溶液,快速搅拌形成均匀溶液后加入三异丙基硅烷与己烷混合溶液,最终的混合溶液置于60℃条件下直至颜色变为黑红色,得到AuCu合金纳米线催化剂；将钼酸钠水合物和硝酸铁水合物溶于水中,把L-半胱氨酸和高纯水加入溶液后搅拌,然后溶液移入到反应釜反应得到FeMoS催化剂。向FeMoS催化剂备用液中加入AuCu合金纳米线催化剂,搅拌分散均匀后室温下静置,待上清液澄清后吸出上清液,底部沉淀在真空干燥箱中干燥,得到用于氮气还原的电催化剂。本发明合成方法简单、反应条件温和,制得产品催化活性较高。(The invention discloses a preparation method of an AuCu-FeMoS electrocatalyst for nitrogen reduction, which comprises the steps of dissolving cuprous chloride and a tetrachloroauric acid hydrate in a mixed solution of hexane and oleylamine, quickly 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 of the final mixed solution becomes black 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, and transferring the solution into a reaction kettle to react to obtain the FeMoS catalyst. 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 bottom sediment in a vacuum drying oven to obtain the electrocatalyst for nitrogen reduction. The synthesis method is simple, the reaction conditions are mild, and the prepared product has high catalytic activity.)

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

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

step S2: dissolving sodium molybdate hydrate and ferric nitrate hydrate in water, keeping the pH value of the solution at 6.5, adding L-cysteine and high-purity water, stirring for 30 minutes to form a uniform and transparent solution, then transferring the solution into a high-pressure reaction kettle, preserving the temperature for 18 hours at 200 ℃, cooling to room temperature, carrying out centrifugal washing on anhydrous ethanol for several times, and dispersing the obtained FeMoS catalyst in the anhydrous ethanol to obtain a standby solution;

step S3: and (4) 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.

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

step S1: preparing 2 mL of mixed solution of hexane and oleylamine with the volume ratio of 1:1, taking 9.88 mg of tetrachloroauric acid hydrate and 1.33 mg of cuprous chloride to be mixed in the mixed solution, quickly stirring to form uniform solution, adding the prepared mixed solution of triisopropylsilane and hexane with the volume ratio of 2:5 of 1.4 mL at room temperature into the uniform solution, standing at 60 ℃ until the color of the solution becomes black red, and obtaining the AuCu alloy nanowire catalyst, wherein the AuCu alloy nanowire catalyst has good flexibility, the diameter is as thin as 1.2 nm, and the length is micron-sized;

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

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

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 consumption of fertilizers worldwide reaches as much as 2 hundred million tons, wherein ammonia is an important raw material for synthesizing fertilizers. The Haberbosch proposal is the most important way in the ammonia industry of the 20 th century, but requires high temperature and high pressure conditions, and causes huge energy consumption and environmental pollution. The electrocatalysis nitrogen reduction is a simple, convenient and energy-saving new scheme, so that the synthesis of the catalyst capable of efficiently and selectively catalyzing nitrogen reduction has important significance.

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

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

Disclosure of Invention

The invention solves the technical problem of providing a 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 for solving the technical problems, and the preparation method of the AuCu-FeMoS electrocatalyst for nitrogen reduction is characterized by comprising the following specific processes:

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

step S2: dissolving sodium molybdate hydrate and ferric nitrate hydrate in water, keeping the pH value of the solution at 6.5, adding L-cysteine and high-purity water, stirring for 30 minutes to form a uniform and transparent solution, then transferring the solution into a high-pressure reaction kettle, preserving the temperature for 18 hours at 200 ℃, cooling to room temperature, carrying out centrifugal washing on anhydrous ethanol for several times, and dispersing the obtained FeMoS catalyst in the anhydrous ethanol to obtain a standby solution;

step S3: and (4) 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 limiting, in the step S1, the charging mass ratio of the cuprous chloride to the tetrachloroaurate hydrate is 2: 15.

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

1. the synthetic method of the AuCu-FeMoS electrocatalyst is simple and has mild reaction conditions.

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

Drawings

Fig. 1 is a TEM image of the AuCu alloy nanowire catalyst prepared in the example;

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

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

Detailed Description

The present invention is described in further detail below with reference to examples, but it should not be construed that the scope of the above subject matter of the present invention is limited to the following examples, and that all the technologies realized based on the above subject matter of the present invention belong to the scope of the present invention.

Examples

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

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

Adding the AuCu alloy nanowire catalyst into the spare liquid of the FeMoS catalyst, stirring and dispersing uniformly, standing at room temperature, sucking out supernatant after the supernatant is clarified, placing bottom sediment in a vacuum drying oven at 45 ℃, and drying to obtain the AuCu-FeMoS electrocatalyst. It can be seen from fig. 2 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 ultrasonically and uniformly coated on carbon paper with the size of 1 x 1 cm, a three-electrode H electrolytic cell system is adopted, the performance of the catalyst is measured through an electrochemical workstation, and the yield of the product ammonia gas is determined by an acid-base neutralization titration method. The ammonia yield and the faradaic 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 property test result of fig. 3, the ammonia yield and the faraday efficiency of the AuCu-FeMoS electrocatalyst are optimal, and the analysis shows that the AuCu nanowires provide a fluffy porous structure similar to a cotton ball shape for the AuCu-FeMoS electrocatalyst, and the FeMoS provides rich nitrogen reduction active sites for the AuCu-FeMoS electrocatalyst, and the synergistic effect of the two increases the electrochemical active surface area, thereby improving the catalytic activity of the catalyst.

The foregoing embodiments illustrate the principles, principal features and advantages of the invention, and it will be understood by those skilled in the art that the invention is not limited to the foregoing embodiments, which are merely illustrative of the principles of the invention, and that various changes and modifications may be made therein without departing from the scope of the principles of the invention.