Fabrication of plasmonic Au/TiO2 nanotube arrays with enhanced photoelectrocatalytic activities

Uniformly dispersed Au nanoparticles (NPs) deposited on the surface of highly ordered TiO2 nanotube arrays (Au/TiO2 NTs) were synthesized through a two-step process including anodization method and microwave-assisted chemical reduction route. The investigation indicated that Au NPs grew uniformly on the walls of TiO2 NTs. Au/TiO2 NTs exhibited excellent visible light absorption due to the LSPR effect of Au NPs. Au/TiO2 NTs exhibited much higher photocurrent density and the photoconversion efficiency of Au decorated TiO2 NTs was about 2.05 times greater than that of bare TiO2 NTs. Besides, the PL intensity of Au/TiO2 NTs was much lower than that of TiO2 NTs, revealing a decrease in charge carrier recombination. The prepared Au/TiO2 NTs exhibited superior photoelectrocatalytic activity and stability in the degradation of MB under simulated solar light irradiation. The synergy effect between nanotubular structures of TiO2 and uniformly dispersed Au nanoparticles, as well as the small bias potential and strong interaction between Au and TiO2, facilitated the Au plasmon-induced charge separation and transfer, which lead to highly efficient and stable photoelectrocatalytic activity.