Controllable synthesis of Au-TiO2 nanodumbbell photocatalysts with spatial redox region

Photocatalytic water splitting has increasingly attracted attention as one of the most useful methods of converting solar energy into chemical fuel. However, the undesirable reverse reaction significantly limits the enhancement of efficiency. Herein, we fabricated an Au nanorods/TiO2 nanodumbbells structure photocatalyst (Au NRs/TiO2 NDs) via a facile synthetic strategy, which has spatially separated oxidation and reduction reaction zones. Owing to the unique structure, the charge separation of these photocatalysts can be significantly improved and the reverse reaction can be efficiently inhibited. The photogenerated electrons were injected from the TiO2 to the Au NRs, and a positively charged TiO2 region and negatively charged Au region were formed under UV irradiation. An enhanced hydrogen production performance was obtained compared with that seen in normal Au-TiO2 heterostructure. Under optimized conditions, the Hz-production rate can reach up to 60,264 gmol/g/h, about six times higher than previously reported Au/TiOz photocatalysts. Besides this, our work also demonstrates the key factors of precise synthesis of the Au NRs/TiO2 NDs structure, which provides a new perspective and experience for the design of similar catalysts. (C) 2019, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.