Enhanced Visible-Photocatalytic Activity of Anodic TiO2 Nanotubes Film via Decoration with CuInSe2 Nanocrystals

The fabrication and photocatalytic properties of visible-light driven CuInSe2/TiO2 heterojunction films are reported. CuInSe2 nanoparticles (NCs) were synthesized using a solvothermal method and then decorated onto self-organized anodic TiO2 nanotube (NT) arrays through an electrophoretic deposition process, forming a CuInSe2 NC/TiO2 NT hetero-structure film. An increase in deposition time produced an increased amount of CuInSe2 NCs loaded onto the TiO2 NT arrays, expanding the light-absorption range of the CuInSe2 NCs/TiO2 NTs film from 400 nm to 700 nm. Photocatalytic degradation results show that activities of the CuInSe2 NCs/TiO2 NTs films were significantly enhanced compared to that of pure TiO2 NTs (degradation rate constant k increased from 3 X 10(-3) min(-1) to > 1 X 10(-2) min-1). Particularly, the CuInSe2 NCs/TiO2 NTs with SO min electrophoretic deposition show the highest degradation rate, k = 1.6 X 10-2 min(-1) (more than 5 times greater than that of the pure TiO2 NTs film), due to optimization of CuInSe2 NCs loading and a well-maintained open TiO2 tube-mouth configuration.