Recent Advances in Furfural Reduction via Electro- And Photocatalysis: From Mechanism to Catalyst Design

Furfural has been considered as one of the most attractive biomass platform compounds, which can be valorized into high-value-added chemicals (e.g., hydrofurorin, 2-methyl furan, tetrahydrofurorin, furfuryl alcohol, tetrahydrofurfuryl alcohol, and 2-methyltetrahydrofuran) and upgraded to functional materials (e.g., synthetic resins, electrical insulation materials, nylon, coatings, and pharmaceuticals). Although the traditional thermocatalytic transformation of furfural is effective, it always requires harsh conditions, especially high temperature and pressure. Accordingly, the reduction of furfural via electro- and photocatalytic approaches has gradually attracted tremendous attention and achieved remarkable progress. Herein, this Review systematically emphasizes the recent advancements in catalysts for valorizing furfural into high-value-added chemicals, biofuels, and additives through electro- and photocatalysis. Moreover, the design strategies of different reactors (i.e., H-cells and flow cells) are clarified. In addition, the application of advanced operando/in situ characterizations and theoretical calculations are highlighted to gain insights into the reaction pathways and catalytic mechanism of the electro- and photocatalytic reduction of furfural. Finally, the current challenges and perspectives are outlined in the field of electro- and photocatalytic furfural conversion.