In-situ structural evolution of multi-site alloy electrocatalyst to manipulate intermediate for enhanced water oxidation reaction

Investigating the reaction mechanism and the rational design of highly efficient electrocatalysts for oxygen evolution reaction play a key role in renewable energy applications. Here, we report a homogeneous multi-metal-site oxyhydroxide electrocatalyst (consisting of Fe doped NiOOH and Cu doped NiOOH) by in-situ electrochemical dealloying of multi-metal-site alloy (consisting of FeNi3 and NiCu alloy). The in-situ structural evolution process manipulates intermediate and enhances the performance of water oxidation. After dealloying, the electrochemical dealloyed catalyst exhibits a small overpotential at large current density (250 mV at 100 mA cm-2), low Tafel slope (34 mV dec-1), remarkably increased ECSA (8-fold larger than before), and superior durability for 200 h at 100 mA cm-2. Such electrocatalyst represents one of the best performances among all reported transition-metal based electrocatalysts, even superior to benchmark RuO2. Operando ATR FT-IR reveals that the electrochemical dealloyed electrocatalyst could manipulate the reaction path based on direct O2 evolution mechanism (DOEM) and facilitate the formation rate of O-O bonds. The fundamental understanding would contribute to the identification and design of the active structure of oxygen evolution electrocatalysts.