Abstract: In this study, three types of Ti-based single/composite oxide nanotube arrays are prepared by anodic oxidation of Ti and typical Ti alloys (Ti-0.2Pd and Ti-6Al-4V). The different fabrication processes and properties of these oxide nanotube arrays are analyzed using SEM, EIS, XRD, EDS, ICP, XPS and UV-Vis DRS. Their photocatalytic activities are determined by degradation of p-nitrophenol in aqueous solution under UV light irradiation. Al and V inside the Ti-6Al-4V alloy-derived nanotube arrays are detected by EDS or XPS. Pd inside the Ti-0.2Pd alloy-derived nanotube arrays cannot be detected by EDS or XPS, but is quantitatively determined by ICP analysis. Incorporation of Al and V significantly deteriorates the photoreactivity of the resultant nanotube arrays, while incorporation of Pd remarkably improves the photocatalytic activity of the resultant titania nanotube arrays powder. The presence of Pd element not only enhances the light absorption, but also facilitates the sulfur poison resistance and the separation of photogenerated charge carriers. Excessive dosage of Al and V element results in structure defect as recombination center and limits the separation of photogenerated charge carriers. This study suggests that anodization of Ti-0.2Pd alloy, rather than pure Ti metal, allows to produce high-performance photocatalysts for environmental and energy applications.

Key words: nanotube arrays, anodic oxidation, Ti alloys, photocatalysis, sulfur poison resistance