Influence of the functional groups of multiwalled carbon nanotubes on performance of Ru catalysts in sorbitol hydrogenolysis to glycols

Different functional groups (i.e. -NH2, -COOH, -OH and nitrogen-doping) modified CNTs (denoted as AMCN, CMCN, HMCN and NMCN, respectively) supported ruthenium catalysts (Ru/AMCN, Ru/CMCN, Ru/HMCN and Ru/NMCN) were prepared by incipient wetness impregnation method. They were fully characterized by XRD, TG, Raman, XPS, TPD and TEM to elucidate the relationship between the physical property and their catalytic performance. TEM results shown that Ru particles were well dispersed on the surface for all the samples with the size of 1.48-1.99 nm. The effects of functional groups of carbon nanotubes (CNTs), nitrogen doping and base additive types on activity and selectivity of ethylene glycol (EG) and propylene glycol (1,2-PD) were investigated. In addition, the activity and final products distribution were much influenced by the properties of functional groups on CNTs and the type of metal cation of the base promoters, which probably participated in the reaction for accelerating a retro-aldol reaction for C-C cleavage. Among the catalysts, Ru supported on AMCN exhibited the best catalytic activities and glycols selectivities than on MCN, CMCN, HMCN and NMCN. (C) 2016 Elsevier B.V. All rights reserved.