TiO₂ Quantum Dot-Integrated CoP: The Directed Electron Transfer Effect Optimizes Surface Reconstruction for Efficient Oxygen Evolution

Suppressing the oxidation of transition-metal-based catalysts during the oxygen evolution reaction (OER) is pivotal for the development of cost-effective and efficient water electrolysis for hydrogen production. CoP, with its excellent electrical conductivity and inherent catalytic activity, shows great promise as an OER electrocatalyst. However, its poor structural stability during the OER, primarily due to overoxidation-induced unstable high-valence states, limits its application. In this study, we introduce a novel strategy that uses TiO 2 quantum dots (QDs) to optimize CoP reconstruction via directed electron transfer. The resulting TiO 2 QDs/CoP electrocatalyst features improved adsorption/desorption and reduced Co leaching, enabled by TiO 2 -to-Co electron donation that increases the surface Co 2 + /Co 3 + ratio. In alkaline media, TiO 2 QDs/CoP achieves an OER overpotential of 246 mV at 10 mA cm – 2 and maintains excellent stability with minimal overpotential loss after 200 h at 100 mA cm – 2 . Our results suggest that controlling excessive oxidation is a viable approach to enhance the performance of the OER of transition-metal catalysts.