Heat‐Triggered Ferri‐to‐Paramagnetic Transition Accelerates Redox Couple‐Mediated Electrocatalytic Water Oxidation
Duanduan Liu, Mengfei Lu, Depei Liu, Shicheng Yan, Wei Zhou, Lunyong Zhang, Zhigang Zou
Abstract
Abstract Redox couple oxidation as an initial step of water oxidation may be key for high electricity consumption in the electrochemical oxygen evolution reaction (OER). Here, a heat‐induced magnetic transition strategy is reported to speed up the oxidation kinetics of redox couples. The activation energy of Ni 2+ /Ni 3+ redox couple oxidation is sharply decreased by heating the Ni 0.67 Fe 0.33 O x H y catalyst above a Curie temperature ( T c ) of 70 °C. In such a strategy, heat instead of electricity drives the spin flipping of Ni 2+ /Ni 3+ oxidation through heat‐sensitive ferri‐to‐paramagnetic spin state changes. As a result of magnetic transition‐assisted efficient heat‐electricity coupling, Ni 0.67 Fe 0.33 O x H y exhibits the lowest OER overpotential of 221 mV at 100 mA cm −2 at 90 °C in alkaline electrolytes, outperforming the benchmark IrO 2 catalyst. The findings provide new insights into the design of efficient heat–electricity complementary OER devices.