Fully-exposed Pt-Fe cluster for efficient preferential oxidation of CO towards hydrogen purification
Zhimin Jia, Xuetao Qin, Yunlei Chen, Xiangbin Cai, Zirui Gao, Mi Peng, Fei Huang, Dequan Xiao, Xiaodong Wen, Ning Wang, Zheng Jiang, Wu Zhou, Hongyang Liu, Ding Ma
Abstract
Abstract Hydrogen is increasingly being discussed as clean energy for the goal of net-zero carbon emissions, applied in the proton-exchange-membrane fuel cells (PEMFC). The preferential oxidation of CO (PROX) in hydrogen is a promising solution for hydrogen purification to avoid catalysts from being poisoned by the trace amount of CO in hydrogen-rich fuel gas. Here, we report the fabrication of a novel bimetallic Pt-Fe catalyst with ultralow metal loading, in which fully-exposed Pt clusters bonded with neighbor atomically dispersed Fe atoms on the defective graphene surface. The fully-exposed PtFe cluster catalyst could achieve complete elimination of CO through PROX reaction and almost 100% CO selectivity, while maintaining good stability for a long period. It has the mass-specific activity of 6.19 (mol CO )*(g Pt ) −1 *h −1 at room temperature, which surpasses those reported in literatures. The exhaustive experimental results and theoretical calculations reveal that the construction of fully-exposed bimetallic Pt-Fe cluster catalysts with maximized atomic efficiency and abundant interfacial sites could facilitate oxygen activation on unsaturated Fe species and CO adsorption on electron-rich Pt clusters to hence the probability of CO oxidation, leading to excellent reactivity in practical applications.