Cr-free Cu-catalysts for the selective hydrogenation of biomass-derived furfural to 2-methylfuran: The synergistic effect of metal and acid sites

Abstract Our work focuses on exploring Cr-free Cu-catalysts for the highly efficient conversion of biomass-derived furfural to value-added bio-fuel 2-methylfuran. Three supported Cu-catalysts (Cu/SiO2, Cu/Al2O3, and Cu/ZnO) were prepared by the typical precipitation method, and Cu/SiO2 catalyst exhibited the best catalytic performance with an 89.5% yield to 2-MF. A series of characteristic results indicated that the high yield of 2-methylfuran on Cu/SiO2 catalyst was assigned to synergistic effect of metal and the weak acid sites. Among them, Cu/ZnO catalyst exhibited maximum furfuryl alcohol selectivity because of the large Cu particles, while Cu/Al2O3 catalyst had low 2-methylfuran selectivity due to the insufficient weak acid sites. For Cu/SiO2 catalyst, the highly dispersed Cu particles and the strong metal-support interaction are propitious to its superior catalytic activity. Therefore, copper species are composed on different supports as a result of the different interaction of metal-support to affect their catalytic activity, while products selectivity is related to the acidic property of catalyst. In addition, temperature programmed desorption of furfural indicated that the adsorption–desorption properties of catalyst surface species would influence the rate of furfural hydrogenation.