Hydrogenation of bio-oil-derived oxygenates at ambient conditions via a two-step redox cycle

A key challenge in upgrading bio-oils to renewable fuels and chemicals resides in developing effective and versatile hydrogenation systems. Herein, a two-step solar thermochemical hydrogenation process that sources hydrogen directly from water and concentrated solar radiation for furfural upgrading is reported. High catalytic performance is achieved at room temperature and atmospheric pressure, with up to two-orders-of-magnitude-higher hydrogen utilization efficiency compared with state-of-the-art catalytic hydrogenation. A metal or reduced metal oxide provides the active sites for furfural adsorption and water dissociation. The in situ-generated reactive hydrogen atoms hydrogenate furfural and biomass-derived oxygenates, eliminating the barriers to hydrogen dissolution and the subsequent dissociation at the catalyst surface. Hydrogenation selectivity can be conveniently mediated by solvents with different polarity and metal/reduced metal oxide catalysts with varying oxophilicity. This work provides an efficient and versatile strategy for bio-oil upgrading and a promising pathway for renewable energy storage.