Fabrication of multi-non-metal-doped TiO2 nanotubes by anodization in mixed acid electrolyte

Multi-non-metal-doped TiO2 nanotubes were fabricated by electrochemical anodization of Ti in the mixed acid electrolyte of C2H2O4·2H2O and HIO3 containing NH4F. The samples were annealed in air and characterized by FE–SEM, XRD, XPS and DRS. The results indicate non-metals of N, F and I are successfully doped into TiO2 nanotubes in aqueous solution by adjusting the electrolyte composition. The multi-non-metal-doped samples display a significant visible-light response. Additionally, the atomic concentration of non-metals is closely related with the electrolyte composition.