Ce-doping induced oxygen vacancies and stabilized AlO structure synergistically enhance RuO₂ stability for acidic...

Developing a structurally stable, strongly electron-donating support for supported RuO₂ catalysts is crucial to achieving durable oxygen evolution reaction (OER) activity, especially in acidic media. In this study, we introduce a Ce, Al co-doping strategy to engineer the MnCo₂O₄ (abbreviated as MCO) spinel support. Ce doping induces oxygen vacancy (O_v) sites that enhance electron transfer at the RuO₂/MCO interface, facilitating improved electronic interactions. The incorporation of low-loading Al further stabilizes the coordinated lattice oxygen, thereby constructing a more robust RuO₂/MCO interface structure. Consequently, the RuO₂/Ce_0.075Al_0.025-MCO catalyst with a Ce: Al molar ratio of 3:1 exhibits superior performance. This shows a low overpotential of 200 mV at 10 mA cm^-2, and operates stably for 400 h at 80 mA cm^-2 without significant degradation. Furthermore, based on a consensus that O_v originates from lattice oxygen removal, we propose a possible mathematical model to describe the relationship between lattice oxygen content and O_v formation energy for RuO₂/Ce_xAl_y-MCO catalysts, providing a thermodynamic framework for understanding how doping ratios influence lattice oxygen behavior. This work provides valuable insights for designing high-performance, acid-stable RuO₂ catalysts.