High-valence metal sites induced by heterostructure engineering for promoting 5-hydroxymethylfurfural electrooxidation and hydrogen generation.

The electrocatalytic 5-hydroxymethylfurfural (HMF) oxidation reaction coupling with hydrogen evolution reaction (HER) serves as a promising strategy to generate both high-value-added products and clean energy, which is limited by the poor catalytic efficiency of bifunctional electrocatalysts and unclear electrocatalytic mechanism for HMF oxidation reaction. Herein, we fabricate a bifunctional NiSe-NiMoO heterostructure nanowire electrocatalyst for the conversion of HMF to 2,5-furandicarboxylic acid (FDCA) and simultaneous H production. As expected, the NiSe-NiMoO exhibits outstanding activity and selectivity toward HMF oxidation reaction. In particular, at a potential of 1.50 V, the yield of FDCA could reach 98 % with a faradaic efficiency of 96.5 %, as well as excellent stability. Density functional theory calculation results demonstrate that the NiSe-NiMoO heterostructure could tune the adsorption energy of HMF, facilitate high-valence active species formation, and enhance electronic conductivity. Furthermore, a two-electrode electrolyzer assembled using NiSe-NiMoO as a bifunctional catalyst requires 1.53 V to acquire a current density of 50 mA cm, which is 201 mV lower than that of water electrolysis. This work provides new insights for designing multifunctional catalysts for biomass upgrading coupled with hydrogen evolution.