X-ray photoelectron spectroscopic studies of anodically synthesized self aligned TiO₂ nanotube arrays and the effect of electrochemical parameters on tube morphology

Abstract

Self aligned TiO₂ nanotube arrays, compared to other TiO₂ nanostructures, have better electron transport properties that will enhance the efficiency of photo catalysis, hydrogen generation by photo-electrolysis and dye sensitized solar cells. Optimization of process parameters by tuning of electrochemical parameters allows the synthesis of TiO₂ nanotube arrays of desired aspect ratio, wall thickness and morphology. In this study TiO₂ nanotube arrays were synthesized at various electrochemical parameters and characterized using field emission scanning electron microscopy (FESEM), Fourier transform infra-red (FTIR) and X-ray photoelectron spectroscopy (XPS). From the results of the study optimum potential range, electrolyte compositions and duration of anodization for the fabrication of smooth walled nanotube arrays of desired aspect ratio are delineated. Presence of surface hydroxyl groups and non-stochiometry in the as prepared and annealed TiO₂ nanotubes were found from FTIR and XPS studies respectively, thus providing rationalization for the enhanced photo catalytic activity of TiO₂ nanotube arrays.