Design principle and synthetic approach of intermetallic Pt-M alloy oxygen reduction catalysts for fuel cells

Developing high-performance Pt-M (M = transition metal) intermetallic alloy catalysts for oxygen reduction reaction (ORR) are key to achieving large-scale applications of proton exchange membrane fuel cells (PEMFCs). It is urgent to clarify the general rules to design and prepare intermetallic Pt-M catalysts with high ORR activity and stability. In this account, the basic principles for disorder-order phase transition in terms of thermodynamics and kinetics are first introduced and our recent efforts in synthesizing fully-ordered Pt-M intermetallic nanocrystals (iNCs) with well-defined L10-ordering structures are described. Then the effective strategies for further enhancing the activity and stability of L10-Pt-M ORR catalysts for PEMFCs are exemplified. We hope that this account will provide some significant insights into the research and development of intermetallic Pt-M alloy ORR catalysts for the applications of PEMFCs and other electrochemical energy conversion technologies in the future.