Enhanced photoelectrochemical performance of CeO2 functionalized TiO2 nanotube arrays with Ag coating

Abstract

The photoelectrochemical performance of Ag coated CeO2 functionalized TiO2 nanotube arrays (AgCeTNT) is investigated here. The sample is prepared via three steps, such as synthesis of TiO2 nanotube by electrochemical anodization, CeO2 functionalization by hydrothermal and Ag coating by Successive Ionic Layer Adsorption and Reaction (SILAR) method. X-ray diffraction (XRD) analysis showed the anatase phase formation after annealing of TiO2 nanotubes. Field Emission Scanning Electron Microscopic (FESEM) images showed the conformal coverage of CeO2 and Ag nanoparticles on the surface of TiO2 nanotubes. Energy Dispersive X-Ray (EDX) analysis confirmed the presence of Ce, Ag, Ti and O in the AgCeTNT sample. Diffuse Reflectance Spectroscopy (DRS) study revealed the enhancement in visible light sensitivity with CeO2 functionalization and further with Ag coating. The photoelectrochemical measurement showed that the AgCeTNT sample exhibits improved photoelectrochemical performance compared to bare TiO2 nanotubes (TNT), CeO2 functionalized TiO2 nanotubes (CeTNT) and Ag coated TiO2 nanotubes (AgTNT) under the illumination of sunlight. This improvement in photoelectrochemical performance happeneddue to the combined effect of favorable band alignment of CeO2 and TiO2 and Surface Plasmon Resonance (SPR) effect of Ag nanoparticles, which lead to superior charge separation, efficient charge transport and enhanced visible light response.