Interfacial interplay in LaCoO3/Ti3C2Tx 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 Ti 3 C 2 T x MXene and LaCoO 3 /Ti 3 C 2 T 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 LaCoO 3 /Ti 3 C 2 T 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 Ti 3 C 2 T x alone. Charge transfer between LaCoO 3 and Ti 3 C 2 T x elevated the Co valence state in LaCoO 3 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.