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

Abstract

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-CO₃^2–) 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.