Proximity Electronic Effect of Ni/Co Diatomic Sites for Synergistic Promotion of Electrocatalytic Oxygen Reduction and Hydrogen Evolution

Abstract The modulation effect manifests an encouraging potential to enhance the performance of single‐atom catalysts; however, the in‐depth study about this effect for the isolated diatomic sites (DASs) remains a great challenge. Herein, a proximity electronic effect (PEE) of Ni/Co DASs is proposed that is anchored in N‐doped carbon (N‐C) substrate (NiCo DASs/N‐C) for synergistic promoting electrocatalytic oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). Benefiting from the PEE of adjacent Ni anchored by four nitrogen (Ni‐N 4 ) moiety, NiCo DASs/N‐C catalyst exhibits superior ORR and HER activity. In situ characterization results suggest Co anchored by four nitrogen (Co‐N 4 ) as main active site for O 2 adsorption‐activation process, which promotes the formation of key *OOH and the desorption of *OH intermediate to accelerate the multielectron reaction kinetics. Theoretical calculation reveals the adjacent Ni‐N 4 site as a modulator can effectively adjust the electronic localization of proximity Co‐N 4 site, promoting the *OH desorption and *H adsorption on Co‐N 4 site, thereby boosting ORR and HER process significantly. This study opens a new opportunity for rationally regulating the electronic localization of catalytic active centers by proximity single‐atom moiety, as well as provides guidance for designing high‐efficiency bifunctional electrocatalysts for promising applications.