MOF-silica hybrid derived high performance K-Cu#SiO2 catalyst for furfural valorization: The functional role of potassium acetate (KAc) in hybridization and copper electronic state

Upgrading biomass platform molecules, e.g. furfural, to value-added fine chemicals has been intensively studied due to its promising potential to substitute the traditional petroleum route producing downstream chemicals. This study presents a high performance K-Cu#SiO2 catalyst derived from the hybrid of copper-based metal-organic-frameworks (Cu-BTC) and silica, for hydrogenation of furfural. The obtained K-Cu#SiO2 having uniformly dispersed copper nanoparticles (~5 nm), achieved a high furfuryl alcohol (FOL) yield (~33 molFOL/molCu h−1), as well as robust recycle utility (trace activity loss after 5 times recycle) at 140 °C and 2.0 MPa. The improved copper metal dispersion and abundant active sites dominating as Cu+/Cu0 species were responsible for the enhanced activity, both of which were closely associated with the functional role of potassium acetate (KAc) serving in the synthesized route. In one respect, the introduced KAc facilitated the Cu-BTC and silica to hybrid a uniform gel by balancing their hydrolysis or crystal growth rates, enabling strengthened copper-silica interactions to yield highly dispersed copper nanoparticles; furthermore, the KAc acted as an electronic regulator to tune the reducibility of copper species on K-Cu#SiO2 catalyst during subsequent N2-calcination. This work could shed a light on the synthesis of high-performance and robust silica-supported copper catalysts for biomass valorization.