Ag and CdS nanoparticles co-sensitized TiO2 nanotubes for enhancing visible photoelectrochemical performance

The Ag and CdS nanoparticles co-sensitization of TiO2 nanotubes (CdS–Ag/TiO2 NTs) were prepared by successive ionic layer adsorption and reaction (SILAR) technique. The phase composition, morphology and optical property were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffusion reflection spectroscopy (DRS). The co-modification of Ag and CdS nanoparticles expanded the photoresponse range of TiO2 NTs from ultraviolet region to 668.7 nm, and the CdS–Ag/TiO2 NTs prepared by SILAR deposition of 5 cycles exhibited higher visible photocurrent and stability against photocorrosion. The detailed electrons transfer mechanism of CdS–Ag/TiO2 NTs was proposed, and photocatalytic activity toward degradation of methyl orange (MO) under visible-light irradiation was also investigated.

► Ag and CdS nanoparticles co-sensitized TiO2 nanotubes were fabricated by the SILAR method. ► The co-sensitization expands the photoresponse range of TiO2 NTs to 668.7 nm. ► Visible light photocurrents and photocatalytic activities of CdS–Ag/TiO2 NTs were studied. ► The electron transfer mechanism of CdS–Ag/TiO2 NTs was proposed.