Hydrothermal synthesis of N-doped TiO2 nanowires and N-doped graphene heterostructures with enhanced photocatalytic properties

Abstract N-doped TiO 2 nanowire/N-doped graphene (N–TiO 2 /NG) heterojunctions are fabricated by a simple hydrothermal method in a solution containing urea. In this hybrid structure, a three-dimensional hybrid photocatalyst was fabricated by using one-dimensional N-doped TiO 2 nanowires penetrating through two-dimensional graphene nanosheets. Compared with TiO 2 nanowire/graphene and N-doped TiO 2 nanowire/graphene composites, the N–TiO 2 /NG heterostructures demonstrate a better photocatalytic performance for the degradation of methylene blue under visible light irradiations, as well as displaying a better recyclability. It is found that the nitrogen atoms originated from the decomposition of urea were not only entered into the lattice of TiO 2 nanowires but also doped into the skeleton of graphene nanosheets. Results show that N doping expands the visible light absorption region of TiO 2 , and N-doped graphene additionally improves the separation and transportation of photogenerated electron–hole pairs plus generating a higher photocurrent, which plays a critical role for enhancing the photocatalytic activity.