Phytic acid-assisted phase-controlled synthesis of nickel phosphides for highly selective hydrogenation of biomass-derived furfural

Developing cost-effective and highly active catalysts for the selective hydrogenation of furfural to target products is significant yet remains a substantial conundrum in the chemical industry. Herein, we present a phytic acid-assisting pyrolysis strategy to phase-controlled synthesis of a series of nickel phosphides catalysts (Ni3P/mSiO2, Ni12P5/mSiO2 and Ni2P/mSiO2), which exhibited phase-dependent catalytic performance in furfural hydrogenation. Ni12P5/mSiO2 achieved the highest yield (97.3%) of cyclopentanone under 1MPa H2 at 150 °C, and Ni3P/mSiO2 could further hydrogenate cyclopentanone to a 60.8% yield of cyclopentanol when the H2 pressure increased to 2MPa. Meanwhile, Ni2P/mSiO2 demonstrated temperature-controlled selectivity for switching between furfuryl alcohol and cyclopentanone. Detailed characterizations and density functional theory calculations elucidated that the differences in catalytic performance were primarily attributed to the hydrogenation ability and acidity of catalysts as well as furfural adsorption configuration, which were determined by the tunable crystal phases of nickel phosphides. This work paves the promising avenue for the rational design of metal phosphide catalysts and harnessing their considerable potential for biomass conversion.