Thermal Switching of Electron Transfer at a VO_{2} Heterointerface for Accelerated Oxygen Evolution.

Structural phase transition offers an effective means to modulate interfacial electronic states and accelerate electron transfer in water electrolysis. Here, we exploit a heat-induced monoclinic-to-tetragonal phase transition in VO_{2} to facilitate electron transfer at VO_{2}/MO_{x}H_{y}(M=Co,Ni,Fe) heterojunction interfaces. The thermally triggered electronic restructuring lowers the Fermi level of VO_{2} relative to MO_{x}H_{y}, promoting the formation of high-valence active species. This significantly accelerates oxygen evolution reaction (OER) kinetics, driving a cascade of catalytic center activation and water oxidation. Our Letter establishes that coupling active catalysts with controllable phase transitions represents a viable strategy for synergistic heat-electricity activation in OER catalysis.