Photoelectrocatalytic Performance Research Of Modified TiO₂ Nanotube Array

Highly ordered TiO2 nanotube arrays(TiO2 NTs)were synthesized through a two-step anodization method.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.TiO2 nanotube arrays sensitized with ZnSe nanoparticles(ZnSe/TiO2 NTs)were successfully fabricated by a two-step anodization followed by an in situ composite synthesis technique.ZnSe nanoparticles(ZnSe NPs)were uniformly deposited on the surface of the TiO2 NTs.The TiO2 NTs shows unique visible light trapping property,which may be attributed to the scattering of light caused by pores or cracks.The results illustrated that the ZnSe NPs sensitized on the TiO2 NTs could significantly enhance the photoelectrochemical performance and photo-conversion efficiency of the TiO2 NTs film.The photoelectrocatalytic activity was investigated by decomposition of methylene blue(MB)solution.The results suggested that the as-prepared ZnSe/TiO2 NTs displayed higher photoelectrocatalytic performance than that of the pure TiO2 NTs,which stemmed from the comprehensive effects between nanotubular structures of TiO2 and uniformly dispersed ZnSe nanoparticles,as well as the small bias.ZnSe and Au nanoparticles co-sensitized TiO2 nanotube arrays(ZnSe/Au/TiO2 NTs)were first successfully fabricated using two-step anodization,microwave assisted chemical reduction and in situ deposition process.The investigation indicated that ZnSe and Au nanoparticles grew uniformly on the surface of TiO2 NTs.The optic property of ZnSe/Au/TiO2 NTs showed a stronger visible light absorption.Enhanced photocurrent(0.61 mA/cm2)of the ZnSe/Au/TiO2 NTs was observed due to the enhanced the photoelectric separation efficiency.Meanwhile,the photoelectrochemical measures clearly demonstrated that the ZnSe/Au/TiO2 NTs had more efficient photoelectrochemical property than the TiO2 NTs.Furthermore,ZnSe/Au/TiO2 NTs also demonstrated the highest photoelectrocatalytic capability and stability during the photoelectrocatalytic degradation of MB.