Design of highly ordered Ag–SrTiO3 nanotube arrays for photocatalytic degradation of methyl orange

Ag–SrTiO3 nanotube arrays were successfully prepared for the degradation of methyl orange (MO) under ultraviolet irradiation. In order to form highly ordered SrTiO3 nanotube arrays, the preparation of TiO2 nanotube arrays by anodic oxidation of titanium foil in different electrolytes was investigated. The selected organic solvents in electrolytes include glycerol, dimethyl sulfoxide and glycol. The results indicate that the morphology of TiO2 nanotube arrays prepared in glycol containing ammonium fluoride electrolyte is more regular. Then SrTiO3 nanotube arrays were synthesized by a hydrothermal method using TiO2 nanotube arrays as the precursor. In order to further improve the photocatalytic activity of SrTiO3 nanotube arrays, Ag nanoparticles were loaded on SrTiO3 nanotube arrays by two sets of experiments. The loaded Ag results in an enhancement of photocatalytic activity of SrTiO3 nanotube arrays. Moreover, the effect of pH on the photocatalytic degradation of MO was also studied.