Unraveling the Electron Transfer Effect of Single‐Metal Ce‐N4 Sites via Mesopore‐Coupling for Boosted Oxygen Reduction Activity

Abstract

AbstractThe development of cerium (Ce) single‐atom (SA) electrocatalysts for oxygen reduction reaction (ORR) with high active‐site utilization and intrinsic activity has become popular recently but remains challenging. Inspired by an interesting phenomenon that pore‐coupling with single‐metal cerium sites can accelerate the electron transfer predicted by density functional theory calculations, here, a facile strategy is reported for directional design of a highly active and stable Ce SA catalyst (Ce SA/MC) by the coupling of single‐metal Ce‐N4 sites and mesopores in nanocarbon via pore‐confinement‐pyrolysis of Ce/phenanthroline complexes combined with controlling the formation of Ce oxides. This catalyst delivers a comparable ORR catalytic activity with a half‐wave potential of 0.845 V versus RHE to the Pt/C catalyst. Also, a Ce SA/MC‐based zinc–air battery (ZAB) has exhibited a higher energy density (924 Wh kgZn−1) and better long‐term cycling durability than a Pt/C‐based ZAB. This proposed strategy may open a door for designing efficient rare‐earth metal catalysts with single‐metal sites coupling with porous structures for next‐generation energy devices.