Defect Engineering of Ultrasmall TiO₂ Nanoparticles Enables Highly Efficient Photocatalysts for Solar H₂ Production...

The conversion of woody biomass to H₂ 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 TiO₂ nanoparticles with tunable concentration of oxygen vacancy defects (V_O-TiO₂) as highly efficient photocatalysts for photocatalytic conversion of woody biomass to H₂. 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-TiO₂ achieves rapid photocatalytic conversion of α-cellulose and poplar wood chip to H₂ in the presence of Pt nanoclusters as the cocatalyst. As expected, the highest H₂ 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.