Utilizing cationic vacancy defects to switch oxygen evolution mechanisms on atomically dispersed ru for enhanced acidic catalytic performance

Abstract

Achieving the oxide path mechanism (OPM) through bimetallic catalysis is a promising approach for developing highly active and stable electrocatalysts for the acidic oxygen evolution reaction (OER). However, optimizing atomic-level and local ligand structures to enhance the synergistic interaction of bimetallic active sites still remains a challenge. Here, through the introduction of tetrahedral Co (Cotet) cationic defects and selectively substituting atomic Ru on the octahedral Co (Cocot) sites in Co3O4, we present an effective strategy to significantly enhance the orbital hybridization and the synergistic interaction of bimetallic active sites. Experimental and theoretical calculations show that this approach facilitates thermodynamic mechanism for diatomic oxygen formation. Cationic defects are utilized as electron acceptors, facilitating the transfer of electrons from Ru to Co, enhancing the overlap in the density of states, and optimizing the d-band center of Ru and Co. Therefore, the orbital hybridization and synergistic effect of bimetallic active sites are improved. Remarkably, the catalyst with a minimal Ru mass loading of around 45.5 μg∙cm−2, featuring a low overpotential of 150 mV and a minimal potential decay rate of just 0.35 mV∙h−1 at 10 mA∙cm−2. Our work offers an effective strategy to enhance the synergistic interaction of bimetallic sites, and the mechanism of cationic defects improve the acidic OER performance of bimetallic sites has been thoroughly investigated, which is expected to contribute to clean energy production.