Anodization of bismuth doped TiO2 nanotubes composite for photocatalytic degradation of phenol in visible light

Abstract

Bismuth doped TiO2 photocatalyst was synthesized in a one-step electrochemical anodization method. Bismuth nitrate Bi(NO3)(3) was used as a bismuth source. The obtained samples were characterized by FE-SEM, XRD, EDX and XPS. The optimum synthesis conditions for bismuth doping were 1.0 M bismuth nitrate in an ethylene glycol electrolyte with anodization at 40 V for 2 h. Compared with undoped TiO2 nanotubes, bismuth doped TiO2 photocatalyst showed a higher photocatalytic activity by a factor of 4.0 for phenol degradation under visible light irradiation. The optimum phenol degradation using a photo-electrocatalytic method was observed at a 0.5 V external bias, and this degradation rate was 5.2 times faster than that observed for undoped TiO2 nanotubes. The doped bismuth TiO2 nanotubes are favorable for the separation of photo-induced electrons and holes, reducing the recombination of charges, and promoting the formation of hydroxyl radicals and superoxides that degrade phenol.