Synergizing Surface Frustrated Lewis Pairs with Ru Nanoheaters for Sacrificial-Agent-Free Photocatalytic CO ₂ Reduction

Photocatalytic CO2 reduction using H2O as the sole electron and proton source represents the ultimate challenge in artificial photosynthesis, yet it is severely hindered by the sluggish kinetics of CO2 adsorption and activation processes. Herein, we report a rationally designed photocatalyst comprising Ru-decorated In2O3 nanorods enriched with surface hydroxyl groups and oxygen vacancies (In2O3−x(OH)y), which drives the conversion of CO2 and H2O into CO and CH4 without sacrificial agents. Atomic-level structural design creates surface frustrated Lewis pairs (FLPs) through the synergy between coordinately unsaturated In sites (Lewis acids) and adjacent In−OH groups (Lewis bases). These FLP sites drastically enhance CO2 adsorption and facilitate its polarization and activation. Meanwhile, Ru nanoparticles not only facilitate electron extraction from the In2O3−x(OH)y nanorods but also function as “nanoheaters” that rapidly raise the local temperature to accelerate water vaporization. The synergistic cooperation between FLPs and Ru cocatalysts fosters balanced and efficient redox kinetics. Consequently, the optimized photocatalyst achieves markedly enhanced CO and CH4 production rates that are 40 and 31 times higher than those of pristine In2O3, respectively, while achieving stoichiometric O2 evolution. This work underscores the pivotal role of surface FLPs and provides a fundamental principle for constructing efficient sacrificial-agent-free photocatalytic systems.