Ru-Mn pair-site triggers key oxygen intermediate for enhanced acidic oxygen evolution reaction kinetics

Abstract

Charge and spin regulation of electrons are identified as a vital factor in improving the oxygen evolution reaction (OER) catalytic activity. Nevertheless, the influence of surface reconstruction on charge and spin structure under complex catalytic reaction conditions has been unintentionally neglected. Correct understanding and targeted regulation of surface reconstruction are the key to prepare high active catalysts. Herein, variable valence states Mn is adopted to regulate Ru-NC, which serves as a model to reduce the localization of Ru 4d structure and stimulate facile charge transfer, achieving accelerated surface reconstruction to generate Ru-O active ingredient with high active to acidic water oxidation. Doping Mn not only accelerates surface reconstruction, but also improves durability by eliminating Ru peroxidation due to Mn-buffered charge compensation. The enhancement of OER activity results from the Mn and O induced Ru spin states to change from intermediate spin to low spin, thereby weakening the interaction with *O intermediates, and promoting *OH adsorption, which benefits the initial step of OER. This study not only provides a strategy to achieve directional reconstruction with the help of metal site asymmetry, but also provides a thorough comprehension of charge and spin dependent acidic OER kinetics.