Catalysis Today, Vol.367, 177-188, 2021
Cu-Al spinel-oxide catalysts for selective hydrogenation of furfural to furfuryl alcohol
Furfuryl alcohol, one of the important platform chemicals for polymer, food, and pharmaceutical industries, was produced by the liquid-phase hydrogenation of furfural. The Cu-Al spinel-oxide catalyst (CuAl2O4) was developed for the furfural hydrogenation to furfuryl alcohol. The spinel CuAl2O4 showed excellent activity as compared to the impregnated Cu/Al2O3 and reported non-noble metal catalysts. The influences of reaction parameters including temperature, time, and H2 initial pressure were systematically investigated. The furfural conversion and the yield of furfuryl alcohol were achieved on CuAl2O4 catalyst at >99 % and >95 %, respectively. The excellent activity of CuAl2O4 catalyst could be attributed to the synergistic effect induced by the interaction between the reduced copper species (Cu0) and the copper spinel host (Cu2+) along with the high H2 sorption ability compared to the impregnated catalyst. Density functional theory (DFT) calculations suggested that the spinel structure had a stronger interaction with furfural and higher amounts of active sites for H2 dissociation, resulting in the lower reaction free energy and energy barriers for the hydrogenation than the impregnated catalyst. Furthermore, it was observed that the CuAl2O4 showed a positive effect on the tolerance against water impurity in the liquid-phase hydrogenation of furfural.