Heteroatom dopants overcome the activity-stability trade-off in RuO2 for acidic oxygen evolution

Abstract

The pursuit of RuO₂ as an alternative acidic oxygen evolution reaction electrocatalyst to IrO₂ holds great promise, yet simultaneously achieving highly active and stable RuO₂ remains an urgent challenge, as conventional strategies often boost one property at the expense of the other. Here, we successfully construct Ta and B co-doped nanoporous RuO₂ with Ru-O-Ta frameworks and Ru-O-B active sites to overcome the activity-stability trade-off. The Ru-O-Ta frameworks stabilize the Ru sites by mediating bridging oxygen and preferentially replenishing oxygen vacancies, thereby facilitating the oxygen evolution reaction through the adsorbate evolution mechanism. Concurrently, the Ru-O-Ta/B sites not only switch the rate-determining step but also lower the energy barriers, thereby enhancing catalytic activity. The Ta/B-RuO₂ exhibits a low overpotential of 170 mV at 10 mA cm⁻², a favorable Tafel slope of 44 mV dec⁻¹, and an outstanding durability. We demonstrate that proton-exchange membrane water electrolyzers equipped with Ta/B-RuO₂ achieves a current density of 1.0 A cm⁻² at a low voltage of 1.6 V and maintains stable operation for 120 h at 200 mA cm⁻².