阅读说明：本技术 一种碳负载纳米银催化剂的制备方法 (Preparation method of carbon-supported nano-silver catalyst ) 是由 戴李宗 刘玲 李云同 吴俣哲 曾碧榕 陈国荣 许一婷 于 2019-08-01 设计创作，主要内容包括：本发明公开了一种碳负载纳米银催化剂的制备方法,以含-NH<Sub>2</Sub>官能团化合物与AgNO<Sub>3</Sub>为原料,通过配位反应合成高分子金属络合物,然后,将该高分子金属络合物高温煅烧,经过其他后处理,制备可用于ORR的碳负载纳米银催化剂。本发明使用的原料来源广泛,价格低廉,且实验操作简单。本发明制备的催化剂,其活性位点Ag纳米颗粒分布均匀,表现出优秀的ORR性能。本发明具有普适性,可以采用不同含-NH<Sub>2</Sub>官能团化合物及溶剂制备。(The invention discloses a preparation method of a carbon-supported nano silver catalyst, which comprises the steps of taking a compound containing-NH 2 functional group and AgNO 3 as raw materials, synthesizing a high-molecular metal complex through coordination reaction, then calcining the high-molecular metal complex at high temperature, and carrying out other post-treatments to prepare the carbon-supported nano silver catalyst for ORR.)

1. A preparation method of a carbon-supported nano-silver catalyst is characterized by comprising the following steps: the method comprises the following steps:

(1) Mixing a compound containing-NH ₂ functional groups with a proper amount of organic solvent, and stirring at room temperature until the compound is completely dissolved;

(2) Dissolving AgNO ₃ in a proper amount of organic solvent;

(3) Dropwise adding the material obtained in the step (2) into the material obtained in the step (1) at a constant speed, stirring at room temperature for reaction for 10-15h after dropwise adding is finished, then centrifuging to obtain a precipitate, and drying the precipitate in vacuum to obtain a high-molecular metal complex;

(4) Heating the macromolecular metal complex to 750-950 ℃ at the heating rate of 4-6 ℃/min and calcining for 1.5-3h in the nitrogen atmosphere, the inert gas atmosphere or the mixed atmosphere of the inert gas and the hydrogen to obtain the carbon-supported nano-silver catalyst;

The compound containing the-NH ₂ functional group is tri (tetraaminophenyl) benzene, tri (tetraaminophenyl) amine or polyethyleneimine.

2. The method of claim 1, wherein the compound containing a functional group-NH ₂ is tris (tetraaminophenyl) benzene or tris (tetraaminophenyl) amine.

3. The method of claim 1, wherein: the organic solvent is dichloromethane, chloroform or 1-methyl-2-pyrrolidone.

4. The method of claim 3, wherein: the organic solvent is dichloromethane or chloroform.

5. The preparation method of claim 1, wherein the molar ratio of the compound containing the-NH ₂ functional group to AgNO ₃ is 1: 1-6.

6. The method according to claim 1, wherein in the step (1), the ratio of the compound having a-NH ₂ functional group to the organic solvent is 0.1 mmol: 15-25 mL.

7. the preparation method according to claim 1, wherein in the step (2), the ratio of AgNO ₃ to the organic solvent is 1 mmol: 10-20 mL.

8. the method of claim 1, wherein: the inert gas is argon.

9. The method of claim 1, wherein: the temperature of the vacuum drying is 55-65 ℃, and the time is 10-15 h.

10. The method of claim 1, wherein: the temperature of the calcination is 850-950 ℃.

Technical Field

The invention belongs to the technical field of organic synthesis electrochemistry, and particularly relates to a preparation method of a carbon-supported nano silver catalyst.

Background

Energy is the basis for human survival and development, and along with the continuous development of society, excessive energy consumption and the imminent exhaustion of various non-renewable resources, the energy crisis faced by people is serious day by day, and the search for new alternative energy is urgent. Fuel cells are widely regarded by researchers as an efficient and clean energy device. However, the fuel cell has a cathode with slow kinetics of oxygen reduction, 6 orders of magnitude slower than the anode hydrogen oxidation, which has greatly hindered the commercial development of fuel cells. Therefore, it is important to develop an efficient Oxygen Reduction Reaction (ORR) catalyst.

Platinum (Pt) based catalysts are currently the most widely used and most effective ORR catalysts, but they still face a number of problems, such as: the cost is high; is easy to be poisoned by CO; in an acid medium, Pt nano particles are easy to oxidize and agglomerate, and the like. These all make the catalyst have a limited useful life, which hinders the commercialization of fuel cells. To accelerate the commercial development of fuel cells, various catalysts in which carbon supports other metal particles have been developed. Among the numerous noble metals, Ag is the best candidate for ORR electrocatalyst due to its relatively low cost, wide source, and relatively high activity in alkaline media. Soo L T et al [ Soo L T, Loh K S, Mohamad A B, et al. Synthesis of silver/nitro-produced graphene oxide through a one-step thermal sol-state reaction for oxygen reduction in a sodium alcohol medium [ J ]. Journal of Power Source, 2016, 324: 412- > the Ag/N-rGO catalyst is prepared by taking metal salt, graphene oxide and melamine as raw materials and calcining at high temperature. The method is simple and easy to operate, but the active sites of the Ag/N-rGO catalyst prepared by taking a small molecular mixture as a precursor are not uniformly distributed, and the catalytic efficiency is not high. Guo J et al [ Guo J, Hsu A, Chu D, et al.Impropriating oxidative reactions on carbon-supported Ag nanoparticles in alkaline solutions [ J ]. The Journal of pharmaceutical Chemistry C, 2010, 114 (10): 4324-4330 ] four Ag/C catalysts with different metal Ag loading amounts are prepared by a citrate protection method, factors influencing the ORR activity of the Ag/C catalyst under an alkaline condition are researched, and the method has important guiding significance on how to design an efficient Ag/C catalyst. In recent years, despite the great progress made by metal nanoparticle/C catalysts in many respects, no catalyst has been developed that can replace Pt/C (20 wt%). Therefore, designing a metal coordination complex by a simple and easy-to-operate method, and then preparing a catalyst having excellent ORR performance is of great significance in promoting the commercialization progress of fuel cells.

Disclosure of Invention

the invention aims to overcome the defects of the prior art and provides a preparation method of a carbon-supported nano silver catalyst.

The technical scheme of the invention is as follows:

A preparation method of a carbon-supported nano-silver catalyst comprises the following steps:

(1) Mixing a compound containing-NH ₂ functional groups with a proper amount of organic solvent, and stirring at room temperature until the compound is completely dissolved;

(2) dissolving AgNO ₃ in a proper amount of organic solvent;

(3) Dropwise adding the material obtained in the step (2) into the material obtained in the step (1) at a constant speed, stirring at room temperature for reaction for 10-15h after dropwise adding is finished, then centrifuging to obtain a precipitate, and drying the precipitate in vacuum to obtain a high-molecular metal complex;

(4) heating the macromolecular metal complex to 750-950 ℃ at the heating rate of 4-6 ℃/min and calcining for 1.5-3h in the nitrogen atmosphere, the inert gas atmosphere or the mixed atmosphere of the inert gas and the hydrogen to obtain the carbon-supported nano-silver catalyst;

The compound containing the-NH ₂ functional group is tri (tetraaminophenyl) benzene, tri (tetraaminophenyl) amine or polyethyleneimine.

In a preferred embodiment of the present invention, the compound containing a functional group of-NH ₂ is tris (tetraaminophenyl) benzene or tris (tetraaminophenyl) amine.

In a preferred embodiment of the present invention, the organic solvent is dichloromethane, chloroform or 1-methyl-2-pyrrolidone.

Further preferably, the organic solvent is dichloromethane or chloroform.

In a preferred embodiment of the invention, the molar ratio of the compound containing the-NH ₂ functional group to AgNO ₃ is 1: 1 to 6.

In a preferred embodiment of the present invention, in the step (1), the ratio of the compound having a-NH ₂ functional group to the organic solvent is 0.1 mmol: 15-25 mL.

in a preferred embodiment of the present invention, in the step (2), the ratio of AgNO ₃ to organic solvent is 1 mmol: 10-20 mL.

In a preferred embodiment of the invention, the inert gas is argon.

In a preferred embodiment of the invention, the temperature of the vacuum drying is 55-65 ℃ and the time is 10-15 h.

in a preferred embodiment of the present invention, the temperature of the calcination is 850-.

The invention has the beneficial effects that:

1. the raw materials used by the invention have wide sources and low price, and the experimental operation is simple.

2. The catalyst prepared by the invention has the advantages that the active site Ag nano particles are uniformly distributed, and the excellent ORR performance is shown.

3. The invention has universality and can be prepared by different compounds containing NH ₂ functional groups and solvents.

Drawings

Fig. 1 is a transmission electron microscope image of carbon-supported nano silver catalysts with different Ag loadings in examples 1 and 2 of the present invention.

Fig. 2 is an electrochemical performance diagram of the carbon-supported nano silver catalyst with Ag loading of 1eq in example 1 of the present invention.

Detailed Description

the technical solution of the present invention will be further illustrated and described below with reference to the accompanying drawings by means of specific embodiments.