Engineering Bulk Compression and Surface Tension Strains Toward Anaerobic 5-Hydroxymethylfurfural Photoconversion

Achieving 2,5-diformylfuran (DFF), a key green biomass plastic monomer, from conventional oxidation of 5-hydroxymethylfurfural (HMF) often involves harsh conditions such as strong alkaline media and is prone to base-catalyzed polymerization side reactions. Herein, we engineered both bulk compression and surface tension strain in rhodium nanoclusters-modified cadmium sulfide nanorods through aluminum doping (Al/Rh_NC-CdS) to boost highly selective anaerobic photocatalytic coproduction of DFF and hydrogen from neutral HMF aqueous solutions under mild conditions. In situ characterization combined with first-principles simulation proves that the bulk compression strain significantly enhances the photogenerated charge separation in Al/Rh_NC-CdS, while the surface tension strain facilitates the rate-determining dehydrogenation oxidation of HMF into the key *C₆H₅O₃ intermediate. These unique characteristics enables Al/Rh_NC-CdS to achieve a 17-, 9-, and 4-fold higher H₂ (776.8 µmol g^{- 1} h^{- 1}) and DFF yield (745.9 µmol g^{- 1} h^{- 1}, with 94.8% selectivity) compared to CdS modified with conventional Rh nanoparticles, nanoclusters, or single atoms. This strain-induced activity enhancement is also observed in other metal nanocluster-loaded CdS systems, highlighting the universal applicability of the proposed strategy. More significantly, Al/Rh_NC-CdS exhibited remarkable yields toward H₂ (270.9 µmol g^{- 1} h^{- 1}) and DFF (255.3 µmol g^{- 1} h^{- 1}, with 95.4% selectivity) in an outdoor concentrated solar-driven photocatalytic system, thus verifying its feasibility for large-scale manufacturing.