Ammonium fluoride 2 Anodic oxidation 2 Chromium compounds 2 Coatings 2 Coupled Hartree-Fock 2 Diffuse reflectance spectroscopy 2 Electrolytes 2 Ethylene 2 Ethylene glycol 2 Ethylene glycol solutions 2 Hamiltonian 2 Heterogeneous photocatalysis 2 Hexavalent chromium 2 Hydrofluoric acid 2 Nanotubes 2 Oxidation 2 Photocatalysis 2 Photocatalytic activities 2 Photocatalytic reactions 2 Scanning electron microscopy 2 Shielding polarizabilities 2 TiO2 nanotubes 2 X ray diffraction 2 Yarn 2 article 2 cyanic acid 2 density 2 electric current 2 electric field 2 electron 2