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.