(Invited) The Exploration of Highly Active Pt and Non-Pt Electrocatalysts for the Oxygen Reduction Reaction in PEMFCs

Abstract

Due to the high Pt loading applied in cathodes of polymer electrolyte membrane fuel cells (PEMFCs), the fuel cell cost remains very high, which greatly hinders its commercialization in different fields. It is well anticipated the Pt loading level should be reduced from the current 0.4 mg/cm2 to less than 0.1 mg/cm2. On the one hand, high active Pt alloy or monolayer catalysts can be obtained by adjusting compositions and structures. On the other hand, the alternative of non-noble metal catalysts (M-N/C, et al.) is considered as the ultimate solution. However, the local mass transfer of oxygen across the active site surface becomes worse due to significant reductions in their amount or activity, seriously affecting the performance of fuel cells1,2. Herein, a series of ultra-low Pt or M-N/C electrocatalysts with both controlled compositions and structures are synthesized and investigated as the oxygen reduction reaction (ORR) electrocatalyst. Corresponding synthetic mechanisms are comprehensively elucidated by advanced physiochemical characterizations combined with density functional theory (DFT). It is believed that the discussion will provide a solid scientific guideline for the development of highly efficiently electrocatalysts for low-cost PEMFCs. Keywords: highly active, low-Pt, non-Pt, oxygen reduction reaction, proton exchange membrane fuel cells, density functional theory Reference [1] W. Xia, A. Mahmood, Z. Liang, R. Zou, S. Guo, Angewandte Chemie International edtion, 2016, 55, 2650.[2] U. Martinez, S.K Babu, E.F. Holby, P. Zelenay, Current Opinion in Electrochemistry, 2018, 9, 224. Acknowledgements This work was supported in part by National Natural Science Foundation of China (21975157) and the National Key Research and Development Program of China (2016YFB0101201 and 2016YFB0101312).