Abstract
Designing highly durable and active electrocatalysts applied in polymer electrolyte membrane (PEM) electrolyzer for the oxygen evolution reaction remains a grand challenge due to the high dissolution of catalysts in acidic electrolyte. Hindering formation of oxygen vacancies by tuning the electronic structure of catalysts to improve the durability and activity in acidic electrolyte was theoretically effective but rarely reported. Herein we demonstrated rationally tuning electronic structure of RuO2 with introducing W and Er, which significantly increased oxygen vacancy formation energy. The representative W0.2Er0.1Ru0.7O2-δ required a super-low overpotential of 168 mV (10 mA cm-2) accompanied with a record stability of 500 h in acidic electrolyte. More remarkably, it could operate steadily for 120 h (100 mA cm-2) in PEM device. Density functional theory calculations revealed co-doping of W and Er tuned electronic structure of RuO2 by charge redistribution, which significantly prohibited formation of soluble Rux>4 and lowered adsorption energies for oxygen intermediates.