Recent advances in heterogeneous catalytic hydrodeoxygenation of biomass-derived oxygenated furanics mediated by formic acid

Abstract

The hydrodeoxygenation is a prominent valorization approach to upgrade biomass-derived platform compounds, i.e. furfural (FF) and 5-hydroxymethylfurfural (HMF), into the value-added fuels and chemicals. As a promising alternative to molecular H2, formic acid (HCOOH) has been extensively investigated as a liquid organic hydrogen donor for the transfer hydrogenation of biomass derivatives. In this study, the recent advances in the heterogeneous catalytic HCOOH-mediated hydrodeoxygenation processes of FF and HMF (especially, the hydrogenation of C=O bond and hydrogenolysis of C–O bond) are systematically reviewed by summarizing the heterogeneous catalysts developed and reaction conditions reported in literature. Furthermore, the reaction mechanisms including the individual and combined activations of hydrogen donor (HCOOH) and substrates (FF and HMF) on the catalyst surface are also discussed in order to provide fundamental insights into the associated reaction mechanisms for the future catalyst design. It is believed that this review may serve as a concise guideline on the development of heterogeneous catalysts for the upgradation of biomass-derived oxygenated furanics using HCOOH as the hydrogen donor.