Single-Atom Ru Anchored Mesoporous TiO₂ Phase-Junction Promotes Photocatalytic Biomass Conversion

Constructing advanced semiconductor nanoreactors is an effective route to boost the efficient photocatalytic conversion of biomasses to high-value-added products. Herein, single-atom anchored flower-like mesoporous TiO₂ nanoreactors with tunable anatase-rutile crystalline phases are prepared via a micelle-interface confined co-assembly strategy (Ru_0.5/A&R-TNs). This approach not only facilitates the introduction of various monatomic/diatomic (e.g., Ru, Mo, Pd, Pt, etc.) sites but also spontaneously induces the TiO₂ phase transformation from anatase to rutile, achieving precise control of two-phase ratios. The interface of the two phases with abundant oxygen vacancies (O_v) facilitates the adsorption and activation of 5-hydroxymethylfurfural (HMF), which exhibits a high photocatalytic HMF oxidation to DFF (selectivity of 90.8%). Based on the optimal phase compositions, the doping of Ru single-atom further exhibits a high atom utilization and suitable electronic structure. Therefore, the Ru_0.5/A&R-TNs achieve the cascade conversion from HMF to 5-formyl-2-furoic acid with a selectivity of 75.8%. This research provides innovative ways for single-atom catalyst synthesis, and the mechanism of synergistic catalytic action may provide new guidance for the photocatalytic conversion of high-value-added products from HMF.