Heterobimetallic catalysis for lignocellulose to ethylene glycol on nickel-tungsten catalysts: Influenced by hydroxy groups.

The superficial chemical environment of the catalyst supports played an important role in heterometallic catalysts preparation. The functions of hydroxy groups on the surface of SiO 2 nanosphere was investigated in catalyst preparing and cellulosic biomass conversion to ethylene glycol (EG). The results demonstrated that 15%Ni-20%W/SiO 2 -OH catalyst was favorable for EG production, with the highest yield of 63.1 and 42.1% from microcrystalline cellulose and hardwood pulp, respectively. The characterization and activity tests suggested that the existence of hydroxy groups could promote the formation of more Ni-W alloys (e.g. NiW, Ni 4 W) under the same preparing condition, which supplemented and enhanced the incorporation of intrinsic nickel and tungsten catalytic activity, especially for enhancement of retro-aldol condensation reaction. Moreover, the metallic Ni 0 was generated in higher amount when supported on hydroxy-rich SiO 2 , boosting hydrogenation of the unsaturated intermediates. Finally, the reusability investigation of the catalyst implied that embedded Ni and W in alloys could inhibit leaching of metals in pressurized hot water. [ABSTRACT FROM AUTHOR]