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

ABSTRACT 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 *C 6 H 5 O 3 intermediate. These unique characteristics enables Al/Rh NC ‐CdS to achieve a 17‐, 9‐, and 4‐fold higher H 2 (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 H 2 (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.