A Cu doped RuO2 catalyst for efficient and durable acidic water oxidation

Producing hydrogen by water electrolysis in acidic system is essential for advancing the proton-exchange membrane water electrolyzer (PEMWE) and maintaining the global sustainability. However, excavating highly active and durable catalysts for anodic oxygen evolution reaction (OER) in acid medium remains a great challenge due to the sluggish kinetics of OER and the severe catalyst dissolution. In this work, we developed a Cu doped RuO2 catalyst (Cu-RuO2@CP) through simple drop casting and low temperature pyrolysis procedures. The incorporation of Cu into RuO2 executes complicated responsibilities: improving OER activity by raising more oxygen vacancies and accelerating the charge transfer between solid-liquid interface; strengthening the long-term durability via suppressing the over-oxidation of RuO2 into soluble RuO4; lowering the catalyst cost by replacing with less expensive Cu. Hence, the Cu-RuO2@CP exhibits excellent activity and stability in 0.5 M H2SO4 electrolyte, requiring a low overpotential of 200 mV to achieve 10 mA cm(-2) and preserving stability for almost 500 h. Moreover, the overpotential is as low as 397 mV even when operating under an industrial-level current density of 1000 mA cm(-2), paving a new way to develop high performance OER electrocatalyst in acidic environment to promote the large-scale utilization of PEMWE.