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.

Na2Ta2O6 nanotube arrays were synthesized by hydrothermal method using Ta2O5 nanotube arrays as a precursor. The loaded Pt enhances the photocatalytic activity for water splitting of Na2Ta2O6 nanotube arrays.Figure optionsDownload as PowerPoint slideHighlights
► Novel Na2Ta2O6 nanotube array films with pyrochlore structure were synthesized.
► Na2Ta2O6 nanotube arrays are active for H2 evolution from aqueous CH3OH solution.
► The effect of hydrothermal conditions on photocatalytic activity was investigated.
► Pt loading can improve the photocatalytic activities of Na2Ta2O6 nanotube arrays.
► Photocatalytic mechanism is proposed based on the experimental results.