Orbital-level band gap engineering of RuO2 for enhanced acidic water oxidation
Xing Wang, Wei Pi, Z. Y. Li, Sheng Hu, Haifeng Bao, Weilin Xu, Na Yao
Abstract
Developing efficient and stable oxygen evolution reaction electrocatalysts under acidic conditions is crucial for advancing proton-exchange membrane water electrolysers commercialization. Here, we develop a representative strategy through p-orbital atoms (N, P, S, Se) doping in RuO2 to precisely regulate the lattice oxygen-mediated mechanism-oxygen vacancy site mechanism pathway. In situ and ex situ measurements along with theoretical calculations demonstrate that Se doping dynamically adjusts the band gap between the Ru-eg and O-p orbitals during the oxygen evolution reaction process. This modulation accelerates electron diffusion to the external circuit, promotes the lattice oxygen-mediated process, and enhances catalytic activity. Additionally, it facilitates electron feedback and stabilizes oxygen vacancies, thereby promoting the oxygen vacancy site mechanism process and enhancing catalytic stability. The resulting Se-RuOx catalyst achieves efficient proton-exchange membrane water electrolysers performance under industrial conditions with a minimal charge overpotential of 1.67 V to achieve a current density of 1 A cm−2 and maintain long-term cyclability for over 1000 h. This work presents a unique method for guiding the future development of high-performance metal oxide catalysts. Improving oxygen evolution in acidic water electrolysis is vital for advancing clean hydrogen production. Here, the authors report that doping ruthenium oxide with selenium enhances efficiency and durability by tuning orbital band gaps, improving electron flow, and stabilizing oxygen vacancies.