Pt基核壳结构质子交换膜燃料电池氧还原催化剂研究进展

Pt-Based Core-Shell Catalyst for Proton Exchange Membrane Fuel Cell

质子交换膜燃料电池在电动汽车动力电源上有广泛的应用前景,其电催化剂的主要成分是Pt,Pt昂贵的价格限制了质子交换膜燃料电池的商业化应用。Pt与3d族过渡金属合金能显著提升Pt催化剂的催化活性,但是活泼的过渡金属元素会在电化学过程和酸性环境下溶出,从而降低燃料电池的整体性能,Pt合金催化剂的稳定尚需提高。Pt基核壳结构催化剂由于成分和结构可调,在提高Pt基催化剂的Pt利用率、催化活性和稳定上有很大潜力,是质子交换膜燃料电池催化剂的研究热点之一。本文按照Pt基核壳结构催化剂的成分划分,从合成方法、结构设计与表征、催化活性、稳定性等方面综述了最近几年Pt基核壳结构催化剂的研究进展。已有研究显示通过控制催化剂纳米尺度的结构和成分分布,包括控制Pt壳层厚度、核与壳的成分、催化剂尺寸和形貌,设计多层核壳结构的催化剂和对催化剂进行后处理等途径,可以制备出各种结构的Pt基核壳结构催化剂,并对壳层Pt原子形成不同程度的电子转移效应和几何晶格应变,提高了催化剂的催化活性和稳定性。

Proton exchange membrane fuel cell has good prospects for automotive applications. The main component of its electrocatalysts is Pt,and the high cost of Pt has limited the commercial applications of proton exchange membrane fuel cells（PEMFCs）. Pt alloyed with the 3d transition metals is more active for the oxygen reduction reaction（ORR） compared to pure Pt catalysts,but the active3 d transition metals are prone to be dissolved by electrochemical or acid treatment,which leads to the performance degradation of PEMFCs. The stability of Pt alloy catalysts needs to be improved further. As the structure and composition of Pt-based core-shell catalyst can be tuned to improve the Pt utilization and stability,it is one kind of the highlighted catalysts for the proton exchange membrane fuel cells. In this paper,recent progress in the synthetic method,structure design and characterization,catalytic activity and stability of Pt based core-shell catalysts based on composition of the catalyst was reviewed. Pt based catalysts with various structures could be prepared by controlling the nanoscale structure and composition of the catalyst,including Pt shell thickness,composition of the core and shell,particle size,and particle shape. These different structures showed different degrees of electron transfer effect and geometric lattice strain on Pt in shell,which might improve the ORR activity and stability of the catalyst.