Rare Earth-Transition Metal Oxides Catalyst for Highly Efficient Oxygen Evolution Reaction with Lattice Oxygen Mediated Mechanism

Abstract

As global attention to environmental sustainability continues to grow, hydrogen energy is emerging as a crucial alternative energy source. Among various hydrogen production methods, water electrolysis stands out due to its environmental friendliness and efficiency. However, the overall performance of this process is significantly limited by the sluggish kinetics of the oxygen evolution reaction (OER). Therefore, the development of high-performance OER catalysts is of great importance. Commercial catalysts based on noble metals such as Ru and Ir exhibit excellent activity, but their scarcity and high cost present substantial barriers to large-scale application. Accordingly, there is an urgent demand for cost-effective, highly active, and stable alternative catalysts. In this study, rather than introducing novel metals, we focused on cerium (Ce), which possesses an f-orbital electronic configuration and readily shifts between oxidation states. The co-deposition of cerium with a transition metal led to an increased population of highly oxidized metal species, resulting in a distinct OER mechanism compared to pristine transition metal oxides (TMO) or CeO 2 . The CeO 2 /TMO heterostructure exhibited outstanding electrocatalytic performance, achieving a low overpotential of approximately 160 mV and a Tafel slope of 32.68 mV dec - 1 , indicating fast reaction kinetics. In addition, the catalyst demonstrated excellent stability under harsh conditions, maintaining performance over 100 hours at a high current density of 500 mA cm - 2 , with only half the overpotential increase observed in pure CeO 2 or TMO systems. These results confirm that the enhanced performance and durability originate from a lattice oxygen-mediated (LOM) mechanism. Our approach highlights the potential of Ce-based heterostructures as promising candidates for next-generation OER catalysts.