Optimization of Ag loaded TiO2 nanotube arrays for plasmonic photoelectrochemical water splitting

In this paper we report on a notable improvement of the photoelectrochemical (PEC) properties of highly ordered Ag loaded TiO2 nanotube arrays (Ag/TNT). Electrochemical anodization and sequential chemical bath deposition with an optimum ratio of precursors were employed for the production of an Ag/TNT nanocomposite. X-ray diffraction analysis (XRD) and scanning electron microscopy SEM images indicate that the Ag nanoparticles were deposited completely on the surface of the pore wall of TiO2 nanotube arrays. The photoelectrochemical measurements, including LSV, chronoamperometry and EIS, indicate that the Ag/TNT sample with a ratio of 1 precursors exhibited the maximum photoelectrochemical efficiency with a photocurrent density of about 300 µA, which is at least 3 times greater than a pure TNT sample. PEC and EIS measurements show that because of the localized surface plasmon resonance (LSPR) effects of Ag nanoparticles, an effective separation of photogenerated electron-hole pairs occurs that led to a reduction of charge transfer resistance at the interface and enhanced the PEC properties of the Ag/TNT sample.