Spiky nanohybrids of TiO2/Au nanorods for enhanced hydrogen evolution and photocurrent generation

Abstract

The fabrication of photocatalysts to achieve efficient utilization of renewable solar energy has attracted broad interest. Herein, a plasmonic spiky TiO₂/Au nanorod (NR) nanohybrid was prepared by in situ nucleation and growth of spiky TiO₂ in AuNR colloidal solution. The spiky TiO₂/AuNR nanohybrids demonstrated enhanced hydrogen evolution activity and photocurrent generation under both visible light and simulated solar light irradiation as compared to bare spiky TiO₂ nanoparticles and commercial TiO₂. Specifically, the spiky nanohybrids displayed a high H₂ production rate of 1.81 mmol g⁻¹ h⁻¹ under simulated solar light irradiation, which is 1.7 times higher than that of TiO₂/Au nanosphere nanohybrids, and remain stable for three cycles. The improved photocatalytic H₂ evolution demonstrated by the nanohybrids can be ascribed to the coupling effect of the AuNRs and the unique spiky structure. Furthermore, the charge transfer process during H₂ evolution was investigated by photocurrent and electrochemical impendence spectroscopy (EIS) measurements. A fast and stable photocurrent was observed for the spiky TiO₂/AuNR nanohybrid photoelectrode under both visible light and simulated solar light irradiation, while the EIS plots indicate a rapid charge transfer within the nanohybrids. Such a nanohybrid with a bio-inspired structure will afford new insights for the fabrication of novel photocatalysts.