Organic-inorganic hybrid materials for catalytic transfer hydrogenation of biomass-derived carbonyl-containing compounds

Upgrading biomass-derived platform molecules into valuable chemicals and biofuels is critical in bio-refinery to establish bio-based sustainable chemical processes. Catalytic transfer hydrogenation represents a fascinating strategy for the reductive upgradation of bio-based oxygenated compounds owing to bypassing the potential security risks and tedious safety precautions associated with using flammable and explosive pressurized H₂. Organic-inorganic hybrid materials (OIHMs), bearing the merits of strong Lewis acid-base ability, high specific-surface-area and pore size, tunable structure/properties and easy preparation, have been confirmed to be promising catalysts for transfer hydrogenation. In this contribution, an overview of OIHMs in transfer hydrogenation of bio-based oxygenated compounds is presented, which mainly involves diverse organic ligands with oxygen-rich groups like −OH, −COOH, −PO₃H₂, and − SO₃H for constructing OIHMs. The corresponding characterization means for clarifying the structures/properties of OIHMs, structure-reactivity relationships, reaction pathways and/or mechanisms together with catalyst durability are elucidated. In addition, the general challenges and future research on the applications of OIHMs in transfer hydrogenation are also discussed. Expectedly, this review can provide an instructive viewpoint for the rational design and practical application of OIHMs in reductive upgrading of bio-based oxygenated compounds via hydrogen transfer processes.