Surface-active site engineering: Synergy of photo- and supermolecular catalysis in hydrogen transfer enables biomass upgrading and H2 evolution

The appropriate regulation of photocatalyst band structure by simultaneous introduction of active sites is an effective strategy in constructing efficient photocatalytic systems for biomass valorization. Herein, a renewed host–guest photocatalyst (Ov-WO 3 @CB[5]) prepared by anchoring cucurbit[5]uril on oxygen vacancy-rich WO 3 was efficient for reductive upgrading of biomass derivatives using NH 3 -BH 3 , such as cascade photocatalytic hydrogenation-cyclization of ethyl levulinate to γ-valerolactone (up to 99 % yield) at 25 °C in 1 h, and quantitative production of primary/secondary bio-alcohols or arylamines from various aldehydes/ketones or nitroarenes, respectively. Also, the rate of H 2 production by direct photocatalytic hydrolysis of NH 3 -BH 3 could reach 5.75 mL h −1 g −1 . The inclusion of cucurbit[5]uril effectively adjusted the semiconductor band structure and enhanced migration efficiency of photo-generated carriers, and the hydrophobic cavity of cucurbit[5]uril favored the entrance of NH 3 -BH 3 , as elaborated by theoretical calculations. Properly engineering supramolecular surface-active sites based on interface host–guest chemistry opens new avenues for reductive upgrading of biomass and hydrogen evolution.