Au/NiO Composite: A Catalyst for One-Pot Cascade Conversion of Furfural

Furfural is a promising renewable platform chemical that is widely produced from lignocellulosic biomass and has received significant attention as a sustainable precursor for the production of chemicals and fuels. To date, one-pot conversion of furfural with cellulosic ethanol is mostly limited to the synthesis of C-5-C-7 hydrocarbons, poising a challenge for the production of high-energy density fuel from biomass-derived compounds. In this study, we present gold nanoparticles supported over nickel oxide (Au/NiO) as robust catalysts for selective conversion of furfural to hydrocarbons. The catalysts present similar to 92% furfural conversion with similar to 81% selectivity toward the production of C-7 and C-9 hydrocarbons through a one-pot cascade reaction, viz., cross-aldol condensations in the presence of ethanol, O-2, and K2CO3, followed by a hydrogenolysis process using H-2(g). Results indicate the unprecedented production of C-9 from furfural and ethanol is yielded via in situ cross-aldol condensation of 3-(2-furyl)acrolein, an alpha,beta-unsaturated aldehyde that is evolved in the reaction medium. Analysis shows the promising catalytic performance of the Au/NiO composite for the furfural conversion can attribute with synergic effects at the interface of the Au nanoparticles and the NiO, offering potential active sites for the reaction. This study may provide new guidelines for design of efficient catalysts to transform bio-based platform compounds into biofuels with high energy density.