Defect Engineering of Ultrasmall TiO 2 Nanoparticles Enables Highly Efficient Photocatalysts for Solar H 2 Production from Woody Biomass.

The conversion of woody biomass to H ₂ through photocatalysis provides a sustainable strategy to generate renewable hydrogen fuel but was limited by the slow decomposition rate of woody biomass. Here, we fabricate ultrasmall TiO ₂ nanoparticles with tunable concentration of oxygen vacancy defects (V _O -TiO ₂ ) as highly efficient photocatalysts for photocatalytic conversion of woody biomass to H ₂ . Owing to the positive role of oxygen vacancy in reducing energy barrier for the generation of ^• OH which was the critical species to oxidize woody biomass, the obtained V _O -TiO ₂ achieves rapid photocatalytic conversion of α-cellulose and poplar wood chip to H ₂ in the presence of Pt nanoclusters as the cocatalyst. As expected, the highest H ₂ generation rate in α-cellulose and poplar wood chip system respectively achieve 1146 and 59 μmol h ^-1 g ^-1 , and an apparent quantum yield of 4.89% at 380 nm was obtained in α-cellulose aqueous solution.