Space-induced charge carriers separation enhances photocatalytic hydrogen evolution on hollow urchin-like TiO2 nanomaterial

Abstract

Abstract The controlled modification of the inner and outer surfaces of hollow nanostructures with dual cocatalysts possessing redox ability is a key factor for improving the charge carrier separation efficiency and surface catalytic reaction efficiency of a catalyst. Herein, a novel hollow urchin-like TiO2 nanomaterial with Pt loaded on the inner surface and RuO2 on the outer surface is reported. The Pt acts as the electron capture centre and is responsible for the reduction reaction, whereas the RuO2 acts as the hole-trapping centre for the oxidation reaction. Compared to nanospheres, the urchin-like structures have a larger specific surface area. Moreover, the as-prepared TiO2 contained numerous single-electron oxygen vacancies (Vo·). The synergy between the highly dispersed catalytic material and spatially separated dual cocatalysts, characterised by hollow structures, a large specific surface area, and oxygen vacancies, greatly increased the activity of the catalyst. When Pt (0.5 wt%) is loaded on the inner surface of the nanomaterials, the hydrogen evolution rate is as high as 2045.1 μmolg−1h−1; moreover, it further improves to 3904.0 μmolg−1h−1 when RuO2 is loaded on the outer shell.