Efficient Cu catalyst for 5-hydroxymethylfurfural hydrogenolysis by forming Cu–O–Si bonds†
Selective hydrogenolysis of C–O bonds of biomass derived precursors has been identified as a promising and essential way to produce fuel additives. Supported transition metals were explored to give efficient reactivity commonly based on a bifunctionality strategy. Here, we report that covalent bonding between SiO2 and Cu features a homologous bifunctional catalyst with metallic Cu and Lewis acidic Cu cations. The catalyst gave superior reactivity for the conversion of 5-hydroxymethylfurfural into 2,5-dimethylfuran. Lewis acidic cations had more predominant roles than metallic sites for C–O hydrogenolysis by stretching and dissociating C–O bonds, whereas they remained inactive for CC bonds. The results rationalize the valence-state-sensitive catalysis for chemistry involving C–O cleavage. The covalent metal–O–Si bonding provides an alternative for developing efficient catalysts since silicates with such a feature are versatile in nature.