Interface-Engineered Frustrated Lewis Pairs in the α-Ga₂O₃/β-In₂O₃ Heterostructure for Efficient Photocatalytic CO₂ Reduction to Solar Fuels

Efficient photocatalyst development for CO2 reduction remains a critical challenge due to inefficient charge dynamics and poor CO2 activation. This study presents a multiphase interface engineering strategy to construct oxygen vacancy-tailored frustrated Lewis acid-base pairs (FLPs) in α-Ga2O3/β-In2O3 heterostructures. Through a two-step ion-exchange/annealing process, spatially separated In3+ (Lewis acids) and Ga–O (Lewis bases) were isolated at the biphasic interface, enabling the synergistic polarization of CO2 molecules. The optimized FLP configuration enhanced charge separation and prolonged carrier lifetime and achieved a CO production rate of 27.7 μmol·g–1·h–1–2.2 times higher than pristine β-In2O3 without sacrificial agents. Mechanistic studies revealed that FLPs facilitated bidentate carbonate (b-CO32–) formation as a key intermediate, followed by protonation to *COOH and subsequent reduction to CO. This work provides fundamental insights into FLP-mediated CO2 activation and establishes a general paradigm for the design of high-performance photocatalysts via interfacial defect engineering.