Catalysis stability enhancement of Fe/Co dual-atom site via phosphorus coordination for proton exchange membrane fuel cell
Yinuo Wang, Xin Wan, Jieyuan Liu, Wenwen Li, Yongcheng Li, Xu Guo, Xiaofang Liu, Jiaxiang Shang, Jianglan Shui
Abstract
Non-precious metal catalysts (NPMCs) are promising low-cost alternatives of Pt/C for oxygen reduction reaction (ORR), which however suffer from serious stability challenge in the devices of proton-exchange-membrane fuel cells (PEMFC). Different from the traditional strategies of increasing the degree of graphitization of carbon substrates and using less Fenton-reactive metals, we prove here that proper regulation of coordination anions is also an effective way to improve the stability of NPMC. N/P co-coordinated Fe-Co dual-atomic-sites are constructed on ZIF-8 derived carbon support using a molecular precursor of C 34 H 28 Cl 2 CoFeP 2 and a “precursor-preselected” method. A composition of FeCoN 5 P 1 is infered for the dual-atom active site by microscopy and spectroscopy analysis. By comparing with N-coordinated references, we investigate the effect of P-coodination on the ORR catalysis of Fe-Co dual-atom catalysts in PEMFC. The metals in FeCoN 5 P 1 have the lower formation energy than those in the solo N-coordinated active sites of FeCoN 6 and FeN 4 , and exhibits a much better fuel cell stability. This anion approach provides a new way to improve the stability of dual-atom catalysts.