Effect of acid treatment on catalytic performance of FeN/ZIF-8 catalyst for oxygen reduction reaction

Abstract

The development of non-noble metal catalysts with high-performance and low-cost for oxygen reduction reaction is one of the main research directions in proton exchange membrane fuel cells.The catalytic performance of the FeN/ZIF-8 catalysts was investigated using ZIF-8, 1, 10-phenanthroline and FeSO4·7H2O as carbon support, nitrogen and iron precursor, respectively. The effects of acid treatment on structure and catalytic performance of FeN/ZIF-8 catalyst were also explored by various techniques. The structure of catalysts was characterized by X-ray diffraction, specific surface area and pore size distribution measurements and transmission electron microscopy, etc. The catalytic activity and stability of the catalysts for oxygen reduction reaction were investigated by linear sweep voltammetry and accelerated degradation test. The results show that the catalysts with ZIF-8 as the carbon support have high initial catalytic activity for oxygen reduction reaction due to their high specific surface area and the existence of Fe3C in catalysts. The acid treatment can remove some unstable iron-containing carbides and disorder carbon in the catalyst. The structure of the FeN/ZIF-8-A catalyst is modified by acid treatment. The higher specific surface area, more abundant mesoporous structure and higher pore volume, as well as the improved resistance to corrosion in acid solution are the key reasons of FeN/ZIF-8-A catalyst with better catalytic activity and stability for oxygen reduction reaction in acid environment.

Keywords

• proton exchange membrane fuel cell
• oxygen reduction reaction
• fen/zif-8
• activity
• acid treatment
• stability