Photocatalytic conversion of biomass-derived 5-hydroxyfurfural (HMF) to value-added 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) is an environmentally friendly process. Here, Ag nanoparticle (NP) supported on TiO 2 (Ag/TiO 2 ) materials with different interfacial structures were fabricated via incipient wetness impregnation. In the photocatalytic oxidation of 5-HMF to HMFCA, low-temperature reduction (473 K) on Ag/TiO 2 could improve the photoinduced charge separation efficiency and promote the reaction due to the "enhanced" localized surface plasmon resonance (LSPR) effects achieved through strong metal-support interaction (SMSI). In particular, 2.5 % Ag/TiO 2 -LTR exhibited superior performance with an HMFCA selectivity of up to 96.7 % under visible-light illumination. In contrast, the photocatalytic efficiency was greatly reduced when the reduction temperature increased to 773 K because of the encapsulation of Ag NPs by a thicker TiO x overlay, which significantly weakened visible-light harvesting. Overall, these findings offer an efficient methodology for designing interfacial enhanced plasmonic photocatalysts for the valorization of biomass.

Herein, the high activity and selectivity of activated carbonsupported molybdenum oxide catalysts (Mo/AC) in the epimerization of glucose to mannose is described. The catalysts afforded near-equilibrium glucose conversion (29.2 %) and selectivity (94.5 %) toward mannose in the epimerization of glucose. The catalysts were characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. It was found that the Mo/AC catalysts were mainly composed of highly dispersed MoO 2 and MoO 3 species. Compared to the soluble MoO 3 catalyst, Mo/AC showed higher stability and better catalytic performances in the epimerization of glucose to mannose. Further, the deactivation of Mo/AC catalysts was attributed to the leaching of molybdenum oxides. Isotope labeling experiments revealed that the deuterium atom at the C-1 position of mannose is formed by glucose-D2 epimerization.

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