Preparation and photocatalytic activity for water splitting of Pt–Na2Ta2O6 nanotube arrays

Na2Ta2O6 nanotube arrays were prepared by hydrothermal method from Ta2O5 nanotube arrays, obtained by anodization of Ta foils, in Na2CO3 solution at 150 °C. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV–vis diffuse reflectance spectra (UV-DRS) and X-ray photoelectron spectroscopy (XPS). Analysis results show that pyrochlore structure Na2Ta2O6 nanotube arrays have been successfully fabricated. The diameters and lengths of Na2Ta2O6 nanotube arrays are 50 nm and 4 μm, respectively. The photocatalytic hydrogen production activities of the as-synthesized Na2Ta2O6 nanotube arrays are highly dependent on the hydrothermal reaction time and Na2CO3 concentration, optimized reaction parameters are obtained. To further improve the photocatalytic activity for hydrogen evolution, Pt loaded Na2Ta2O6 nanotube arrays are prepared by photochemical reduction method. The Pt loaded samples exhibit much higher activity for hydrogen evolution than pure Na2Ta2O6 nanotube arrays. Moreover, the photocatalytic hydrogen properties are rather stable.