Selective hydrogenolysis of 5-hydroxymethylfurfural to 2,5-dimethylfuran with high yield over bimetallic Ru-Co/AC catalysts.

Abstract

Catalytic hydrogenolysis of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) has become a hot topic in the bioenergy field in recent years. It remains a challenge to mediate the activation/hydrogenation/hydrogenolysis of C-O and C[double bond, length as m-dash]O bonds of HMF at high temperatures. Herein, bimetallic Ru-Co/AC catalysts were prepared by the "two-step" reduction method and were used to catalyze the hydrogenolysis of HMF to DMF. The effects of different reduction methods, Ru/Co ratios, and Ru loading on the catalytic performances of the Ru-Co/AC catalysts were investigated, and the physicochemical properties of the catalysts were characterized by TEM, XPS, H2-TPR, etc. It was found that the catalysts reduced by the "two-step" reduction method exhibited better catalytic activities than those fabricated by a single H2 or NaBH4 reduction method. The introduction of Co metals promoted the dispersion of Ru nanoparticles (NPs) on AC and the transfer of electrons from Co to Ru, thereby improving the catalytic activity. An excellent yield of DMF up to 97.9% and 98.7% conversion of HMF were achieved in a short time (1.5 h) under the optimal conditions (200 °C, 1 MPa). Furthermore, the possible reaction pathway for the hydrogenolysis of HMF to DMF over 5%Ru-1%Co/AC catalyst is also discussed. The work shows that the Ru-Co/AC catalysts have great potentials for the conversion of HMF into liquid fuel DMF.