Importance of Magnesium in Cu-Based Catalysts for Selective Conversion of Biomass-Derived Furan Compounds to Diols

Selectively hydrogenating the carbonyl of furfural and opening of the furan ring is challenging but crucial for efficient conversion of furfural to pentanediols, the valuable chemicals. In this study, CuMgAl catalysts with highly dispersed Cu particles and tunable basic sites were synthesized with layered double hydroxides as precursors for hydrogenation of furfural to furfuryl alcohol (FA) and the subsequent hydrogenolysis of FA to 1,2-pentanediol and 1,5-pentanediol. The presence of varied content of Mg in the catalyst promoted dispersion of copper oxide and exposure of metallic copper species, weakened interaction between copper oxides and the carrier, suppressed sintering of metallic copper species, and increased abundance of the basic sites, promoting the catalytic activity/selectivity/stability. Strong chemical adsorption of the furan ring in FA on basic sites of the catalyst suppressed hydrogenation of the furan ring and facilitated opening of the furan ring in FA, the rate-determining step for formation of the diols.