Activating Single‐Atom Ni Site via First‐Shell Si Modulation Boosts Oxygen Reduction Reaction

Abstract Atomically dispersed nitrogen‐coordinated 3d transition‐metal site on carbon support (M‐NC) are promising alternatives to Pt group metal‐based catalysts toward oxygen reduction reaction (ORR). However, despite the excellent activities of most of M‐NC catalysts, such as Fe‐NC, Co‐NC et al., their durability is far from satisfactory due to Fenton reaction. Herein, this work reports a novel Si‐doped Ni‐NC catalyst (Ni‐SiNC) that possesses high activity and excellent stability. X‐ray absorption fine structure and aberration‐corrected transmission electron microscopy uncover that the single‐atom Ni site is coordinated with one Si atom and three N atoms, constructing Ni‐Si 1 N 3 moiety. The Ni‐SiNC catalyst exhibits a half‐wave potential (E 1/2 ) of 0.866 V versus RHE, with a distinguished long‐term durability in alkaline media of only 10 mV negative shift in E 1/2 after 35 000 cycles, which is also validated in Zn‐air battery. Density functional theory calculations reveal that the Ni‐Si 1 N 3 moiety facilitates ORR kinetics through optimizing the adsorption of intermediates.