Ru–O covalency regulated via constructing a RuO2/Cr2O3 heterogeneous interface to boost acidic water oxidation

Abstract

Developing efficient and durable oxygen evolution reaction (OER) catalysts under acidic conditions is crucial for green hydrogen production. Constructing heterogeneous interface structures represents the most promising strategy to overcome the intrinsic activity limitations of electrocatalysts. Here, a catalyst with crystalline–amorphous heterostructure (RuO₂/Cr₂O₃) exhibiting enhanced performance in the acidic OER has been prepared, which achieves a low overpotential of 218 mV at 10 mA cm⁻². X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) analyses indicate that the electron density of Ru is modulated by the interaction with Cr, leading to improved Ru–O bonding characteristics. The heterostructure effectively reduces the charge transfer resistance at the interface between the crystalline and amorphous phases and facilitates the adsorption/desorption of OER intermediates. In situ Raman spectroscopy further reveals that the Ru–O bond interactions are significantly enhanced due to the formation of a heterogeneous interface, which stabilizes the dissolution of Ru species at elevated potential. Mass spectrometry analysis confirmed that lattice oxygen participation was inhibited, contributing to improvements in the durability of the OER, resulting in catalyst stability of over 30 hours at 10 mA cm⁻². This study presents a feasible strategy for the design and development of catalysts with enhanced activity and stability.