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

Photocatalytic CO 2 reduction using H 2 O as the sole electron and proton source represents the ultimate challenge in artificial photosynthesis, yet it is severely hindered by the sluggish kinetics of CO 2 adsorption and activation processes. Herein, we report a rationally designed photocatalyst comprising Ru-decorated In 2 O 3 nanorods enriched with surface hydroxyl groups and oxygen vacancies (In 2 O 3− x (OH) y ), which drives the conversion of CO 2 and H 2 O into CO and CH 4 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 CO 2 adsorption and facilitate its polarization and activation. Meanwhile, Ru nanoparticles not only facilitate electron extraction from the In 2 O 3− 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 CH 4 production rates that are 40 and 31 times higher than those of pristine In 2 O 3, respectively, while achieving stoichiometric O 2 evolution. This work underscores the pivotal role of surface FLPs and provides a fundamental principle for constructing efficient sacrificial-agent-free photocatalytic systems.