Engineering Thermoelectric-Electrocatalytic Coupling in RuO₂/PrCoO₃ Heterointerface for Efficient Oxygen Evolution

The oxygen evolution reaction (OER) is pivotal for diverse electrochemical energy conversion systems; however, it has so far been plagued by sluggish kinetics and excessive energy consumption. In this study, we proposed an innovative thermoelectric-electrocatalytic coupling strategy to enhance OER efficiency by constructing an Ohmic heterointerface through uniform integration of RuO₂ with thermoelectric oxide (PrCoO₃). Combined experimental and theoretical analyses revealed that the thermoelectric potential generated by PrCoO₃ selectively activates the intrinsically inert (101) facet of RuO₂ by lowering *OOH formation barrier, thereby substantially boosting the overall OER performance. Consequently, the RuO₂/PrCoO₃ heterointerface delivered exceptional OER performance under a mild temperature gradient (ΔT) of 175°C, achieving dramatic reduction in overpotential at 10 mA cm^-2 from 300 mV (ΔT = 0°C) to 178 mV, 4 300% increase in current density, and negligible potential loss over 1,000 h. When the catalyst was assembled into an anion exchange membrane water electrolyzer, the cell driven by spontaneous heating reached a low voltage of 2.18 V at a current density of 2.0 A cm^-2, with stable operation for 600 h. These insights into harnessing thermal gradient via integrated electrocatalytic system are crucial for the recovery of industrial waste heat and its conversion into high-value chemicals.