Photo-driven transient frustrated Lewis pairs for catalytic hydrogenation.

Heterogeneous frustrated Lewis pairs (FLPs) have emerged as an effective strategy to transform catalytically inert supports into active sites for hydrogenation reactions. However, the practical application of FLP sites remains limited due to their random spatial distribution and limited capacity to activate H2. To address these challenges, we report the rational design of a highly effective FLP-based catalyst by anchoring isolated Rh atoms onto CeO2, achieving a hydrogenation rate of 35%/h for styrene, remarkably outperforming pristine CeO2 (2.74%/h). It is found that Rh species on CeO2 form interfacial Rh-O-Ce sites, which play a critical role in the heterolytic cleavage of H2 into Rh-H δ- and O-H δ+ species. Upon light irradiation, the hydrogen spillover process is significantly promoted, enabling more efficient migration of activated hydrogen species to FLP sites and thereby facilitating H2 dissociation under mild conditions. Moreover, photoexcitation of CeO2 generates abundant transient FLPs on the surface, which serve as additional active sites for hydrogenation, leading to a substantial enhancement in photocatalytic activity. Similar synergistic effects are also observed when other semiconductor supports are employed, indicating the generality of this strategy. These findings provide a new strategy for designing synergistic dual-active-site systems that integrate interfacial metal-oxide sites with photoinduced FLPs for efficient photocatalytic hydrogenation reactions.