Interfacial interplay in LaCoO₃/Ti₃C₂T_x composites enables kinetic enhancement in electrochemical oxygen evolution

Developing efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for sustainable hydrogen production via water electrolysis. Herein, we report the facile synthesis of single- or few-layer Ti₃C₂T_x MXene and LaCoO₃/Ti₃C₂T_x composite catalysts by a ball milling-assisted exfoliation strategy with urea intercalation. Tafel slope plot was used to obtain the intrinsic Tafel slope of OER for LaCoO₃/Ti₃C₂T_x composite with varying mass ratios. By optimizing the composite ratio, the intrinsic Tafel slope of OER is decreased from 88.6 to 47.1 mV/dec, indicating a shift of rate-determining step (RDS). This enhancement stems from interfacial electronic modulation rather than conductivity and hydrophilicity provided by Ti₃C₂T_x alone. Charge transfer between LaCoO₃ and Ti₃C₂T_x elevated the Co valence state in LaCoO₃ and induced lattice strain, which modulated its electronic structure and shifted the RDS of OER to O–O bond formation. This study highlights the interface engineering in composite catalysts for efficient energy conversion.