Novel (Pt-O x )-(Co-O y ) Nonbonding Active Structures on Defective Carbon from Oxygen-Rich Coal Tar Pitch for Efficient HER and ORR.

Atomic-scale utilization and coordination structure of Pt electrocatalyst is extremely crucial to decrease loading mass and maximize activity for hydrogen evolution reactions (HERs) and oxygen reduction reactions (ORRs). A novel atomic-scale (Pt-O x )-(Co-O y ) nonbonding active structure is designed and constructed by anchoring Pt single atoms and Co atomic clusters on the defective carbon derived from oxygen-rich coal tar pitch (CTP). The Pt loading mass is extremely low and only 0.56 wt%. A new nonbonding interaction phenomenon between Pt-O x and Co-O y is found and confirmed based on X-ray absorption spectroscopy and density functional theory calculations. Based on the (Pt-O x )-(Co-O y ) nonbonding active structure, surface chemical field coupling with electrocatalysis for the HER and ORR is confirmed. It is found that the (Pt-O x )-(Co-O y ) nonbonding active structure exhibits high mass activities of 64.4 A cm -2 mg Pt -1 (at an overpotential of 100 mV) and 7.2 A cm -2 mg Pt -1 (at 0.8 V vs reversible hydrogen electrode) for the HER and ORR, respectively. The values are 6.5 and 11.6 times as much as those of commercial 20% Pt/C. The work provides innovative insight to design and understand efficient active sites of atomic-scale Pt on oxygen-rich CTP-derived carbon supports for electrocatalysis.