Robust Interface Ru Centers for High-Performance Acidic Oxygen Evolution

Abstract

RuO₂ is considered as the state-of-the-art electrocatalyst for the oxygen evolution reaction (OER) in acidic media. However, its practical application is largely hindered by both the high reaction overpotential and severe electrochemical corrosion of the active centers. To overcome these limitations, innovative design strategies are necessary, which remains a great challenge. Herein, robust interface Ru centers between RuO₂ and graphene, via a controllable oxidation of graphene encapsulating Ru nanoparticles, are presented to efficiently enhance both the activity and stability of the acidic OER. Through precisely controlling the reaction interface, a much lower OER overpotential of only 227 mV at 10 mA cm⁻² in acidic electrolyte, compared with that of 290 mV for commercial RuO₂, but a significantly higher durability than the commercial RuO₂, are achieved. Density functional theory (DFT) calculations reveal that the interface Ru centers between the RuO₂ and the graphene can break the classic scaling relationships between the free energies of HOO* and HO* to reduce the limiting potential, rendering an enhancement in the intrinsic OER activity and the resistance to over-oxidation and corrosion for RuO₂.