Improving the electrocatalytic performances of Pt-based catalysts for oxygen reduction reaction via strong interactions with single-CoN4-rich carbon support

Developing platinum-group-metal (PGM) catalysts possessing strong metal-support interaction and controllable PGM size is urgent for the sluggish oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells. Herein, we propose an in-situ self-assembled reduction strategy to successfully induce highly-dispersed sub-3 nm platinum nanoparticles (Pt NPs) to attach on resin-derived atomic Co coordinated by N-doped carbon substrate (Pt/CoSA-N-C) for ORR. To be specific, the interfacial electron interaction effect, along with a highly robust CoSA-N-C support endow the as-fabricated Pt/CoSA-N-C catalyst with significantly enhanced catalytic properties, i.e., a mass activity (MA) of 0.719 A/mgPt at 0.9 ViR‑free and a reduction of 24.2% in MA after a 20,000-cycles test. Density functional theory (DFT) calculations demonstrate that the enhanced electron interaction between Pt and CoSA-N-C support decreases the d-band center of Pt, which is in favor of lowering the desorption energy of *OH on Pt/CoSA-N-C surface and accelerating the formation of H2O, thus enhance the instinct activity of ORR. Furthermore, the higher binding energy between Pt and CoSA-N-C compared to Pt and C indicates that the migration of Pt has been suppressed, which theoretically explains the improved durability of Pt/CoSA-N-C. Our work offers an enlightenment on constructing composite Pt-based catalysts with multiple active sites.