Hydrothermal carbon-supported Ni catalysts for selective hydrogenation of 5-hydroxymethylfurfural toward tunable products

5-hydroxymethylfurfural (HMF), as one of the most important renewable platform-chemicals, is a valuable precursor for the synthesis of biofuels and bio-products. In this work, hydrothermal carbon (HC), with a large specific surface area and plenty of oxygen-containing functional groups, was derived from sucrose via a hydrothermal method, which could facilitate the dispersion and anchoring of Ni. The selectivities to 2,5-bis(hydroxymethyl)furan (BHMF), 2,5-dimethyltetrahydrofuran (DMTHF), and 2,5-dimethylfuran (DMF) were tuned by modulating Ni nanoparticle sizes and Ni/NiO ratios. The yield of BHMF can reach 88% with its selectivity up to 94% on the reduced 10%-Ni/HC catalyst with big Ni particle size; while the total yield of DMF + DMTHF is up to 94.6% at full HMF conversion on the calcined 5%-Ni/HC catalyst with small Ni particle sizes and balanced Ni/NiO ratios; for the calcined Ni/HC catalysts, the synergistic effect between Ni(0), favoring H2 activation and hydrogenation, and NiO, facilitating the hydrogenolysis of C–O bonds, could promote the selective hydrogenolysis of HMF to biofuel production (DMF and DMTHF).