A kind of surface cyanide modified nano-metal material and preparation method thereof

Abstract

The invention provides a simple and green surface cyaniding modified nano metal electrode material, and a synthetic method thereof. According to the preparation method, nano metal (such as platinum and platinum-ruthenium) loaded on conventional carriers, hydrogen peroxide (or Fenton's reagent), and nitrile are mixed so as to obtain a suspension system; and the surface cyaniding modified nano metal electrode material is obtained via synthesizing under ultraviolet light, wherein the suspension system containing Fenton's reagent can be subjected to reaction without ultraviolet light. The nano metal electrode material is subjected to surface cyaniding for the first time; electrode catalysts with special electrochemical properties are obtained; for example, surface cyaniding modified platinum carbon nano catalyst is capable of inhibiting carbon monoxide poisoning, and maintaining oxygen reduction performance in electro-catalytic reduction processes of oxygen, and methanol resistance is improved greatly. According to synthetic processes, extremely toxic substance CN- is not involved; the preparation method is completely green, and is used for synthesizing the surface cyaniding modified electrode material; large-scale cyaniding modification on commercial metal electrode materials can be realized; and the preparation method is suitable for large-scale production.

Description

technical field [0001] The invention relates to the field of chemistry, in particular to a surface cyanide-modified nano-metal material and a preparation method thereof. Background technique [0002] A proton exchange membrane fuel cell (PEMFC) is a device that directly converts chemical energy into electrical energy and has high energy conversion efficiency because it is not limited by the Carnot cycle. The fuel cell is mainly divided into three parts, the anode, the cathode, and the electrolyte. The oxidation reaction of fuel occurs at the anode, and the reduction reaction of oxygen occurs at the cathode. According to different electrolytes, fuel cells are generally divided into acid fuel cells and alkaline fuel cells. The proton membrane is also a part of the fuel cell, it is a hydrogen proton (H + ) of a membrane, hydrogen protons can directly pass through the proton exchange membrane to reach the cathode, while electrons can only reach the cathode through an external c...

AI Technical Summary

Problems solved by technology

[0004] The surface properties of metal catalysts can be changed by surface modification methods to produce catalytic effects different from the original catalysts. So far, cyanide ions (CN - ) to modify the surface of metal catalysts, the most widely used method is the MacArthur-Forrest method, which mainly uses NaCN or KCN as a cyanide source, which poses a fatal threat to the environment and human health. For example, the top international journal Nature Chemistry (IF=23.3) mentioned in the paper (Enhanced electrocatalysis of the oxygen reduction reaction based on patterning of platinum surfaces with cyanide, Nature Chemistry, 2010, Vol 2 , 880-885) that CN - Physisorption on the surface of Pt(111) to form Pt(111)–CN ad , in acidic solution (sulfuric acid, phosphoric acid), this structure can eliminate the adsorption of acid radical (sulfuric acid, phosphoric acid) ions on Pt(111), maintain the active site of Pt, thereby maintaining the original oxygen reduction activity of Pt, but in Alkaline solution (KOH), due to CN - With a negative charge, the resulting Pt(111)–CN ad The surface is also negatively charged, which can then attract the positively charged K + , resulting in CN – K + (H 2 O) x Therefore, due to the steric effect, the active site of Pt is covered, and the oxygen reduction performance will be inhibited (see Fig1-2 of the article for the experimental results, and Fig3 of the article for the model diagram)

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