TiO₂ film supported by vertically aligned gold nanorod superlattice array for enhanced photocatalytic hydrogen evolution

Abstract

Photocatalytic hydrogen generation from water as a renewable non-polluting technique for converting solar energy to chemical energy has recently attracted worldwide attention. However, low hydrogen production efficiency of traditional photocatalysis still remains as a challenge. Here, we report a large area TiO₂ film supported by vertically ordered Au nanorods superlattice array (O-AuNRs/TiO₂), which demonstrates excellent photocatalytic performances of hydrogen evolution from water under solar and visible light irradiation. The O-AuNRs/TiO₂ architecture enables the significant localized surface plasmon resonance (LSPR) enhancement, including both local electromagnetic field effect and hot electron transfer effect, which promotes the photocatalytic hydrogen evolution rate of the TiO₂ film by 58 times. The photocatalytic efficiency of O-AuNRs/TiO₂ exceeds that of the TiO₂ film supported by randomly oriented AuNRs by over five times. Finite difference time domain (FDTD) modeling results support that the strong coupling of O-AuNRs enhances the electromagnetic field intensity along the longitudinal axis in the gaps between adjacent AuNRs and the average electric field enhancement factors at the interface between the AuNRs and TiO₂ of O-AuNRs/TiO₂. This work demonstrates the substantial performance boost of conventional photocatalyst by LSPR enhancement, thus provides a promising tactic to devise highly efficient photocatalytic system for solar energy conversion.