Photoelectrochemical and photocatalytic properties of Ag-loaded BaTiO3/TiO2 heterostructure nanotube arrays

BaTiO3/TiO2 (BT) heterostructure nanotube arrays were fabricated by in situ hydrothermal method using TiO2 nanotubes as both template and reactant. Compared with pure TiO2 nanotube arrays, the BT heterostructures exhibited enhanced photocurrent under UV light irradiation. For further improving the photoelectrochemical performance, Ag nanoparticles were loaded on the surface of BT heterostructure by two different photo-reduction (Ag/BT-P) and chemical reduction (Ag/BT-C) methods. The results showed that the Ag nanoparticles on Ag/BT-C were uniform and dispersed homogeneously, but the Ag nanoparticles on Ag/BT-P were very large, which resulted in the tailored and integrated nanotube structure destroyed. The electrochemical impedance spectra (EIS) indicated that the impedance arc radius of Ag/BT-C was much smaller than Ag/BT-P and the pure BT nanotube arrays, indicating that the enhanced charge carrier separation was achieved on Ag/BT-C. In addition, the Ag/BT-C nanotube arrays exhibited a higher photocatalytic activity for methylene blue (MB) degradation.