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Abstract: Cu2+-doped TiO2 film on stainless steel substrates was prepared using sol–gel method. Based on XRD and SEM analysis results, the as-prepared film was mainly in anatase phase. The film was smooth and the thickness of the film was about 2μm. The UV–vis absorption of Cu2+-doped TiO2 was extended to visible range, which is favorable for the utilization of solar light. The photoelectrochemical properties of the samples were investigated via electrochemical impedance spectrum (EIS). The EIS plots demonstrated that the Cu2+-doped TiO2 can be excited under visible light irradiation and the photo-generated electron–hole pairs can be separated efficiently by applying an external bias. The degradation experiments for methylene blue and methyl orange in different processes showed that the photo-response range of TiO2 could be extended by doping Cu2+ ion and the photocatalytic activity of TiO2 could be enhanced with the help of a forward bias. [Copyright &y& Elsevier]

The FTO/TiO 2 heterojunction photocatalysts were prepared and characterized by XRD, SEM, UV–vis and electrochemical impedance measurement. The effect of F doping level on the optical band gap and conductivity of as-prepared FTO samples, as well as the band alignment of FTO/TiO 2 heterojunction photocatalyst was detailed analyzed. In addition, the change of optical band structure and conductivity caused by F doing was correlated with observed carriers transport properties including charge carriers separation, transport and interface transfer in the FTO/TiO 2 heterojunction photocatalyst. Finally, the photocatalytic activity, photoelectrocatalytic performance and their photocatalytic mechanism were systematically discussed. The primary results demonstrate that the heterojunction structure in the FTO/TiO 2 photocatalyst can effectively separate photogenerated carriers; however, the expense of redox ability is unavoidable. Among these, the FTO(1)/TiO 2 sample displays the highest photocatalytic activity, which is attributed to that the benefit of inhibiting recombination has dominant effect on photocatalytic performance. [ABSTRACT FROM AUTHOR]

Abstract: The Sn4+ doped anatase TiO2 nanocrystals with various amounts of dopant Sn4+ ions were prepared from peroxo-metal-complex precursor by solvothermal method and characterized by XRD, TEM, HRTEM, XPS, ICP-AES and UV–vis spectrophotometer. The experimental results indicated that the dopant Sn4+ substituted Ti4+ in the lattice of TiO2, which reflected in the lattice expansion in both a- and c-direction and change of the binding energy. All the Sn4+ doped TiO2 nanocrystal samples appeared to be anatase evenly with dopant level up to 10mol%. The effect of dopant Sn4+ ions and reaction solvents on physicochemical properties of the obtained Sn4+ doped anatase TiO2 nanocrystals had been discussed. In addition, the growth mechanism and microstructure evolution of Sn4+ doped anatase TiO2 nanocrystals had been suggested. The photocatalytic activity of the Sn4+ doped anatase TiO2 nanocrystals was tested by the degradation of phenol. Compared with the undoped TiO2 sample, the enhanced photocatalytic activity of the Sn4+ doped anatase TiO2 nanocrystals could be attributed to modification of the optical properties and surface state by doping the optimum concentration of Sn4+ ions. [Copyright &y& Elsevier]

Abstract: The preparation of Ti1−x Sn x O2 nanocrystal colloids from peroxo-metal precursor by hydrothermal method was reported in this work. The obtained materials were investigated by means of XRD, Raman, TEM, XPS, ICP-AES, N2 adsorption–desorption measurements (BET), PL and UV–vis spectroscopies technology. Photocatalytic degradation of phenol was studied under UV illumination. The results indicated that Ti1−x Sn x O2 nanocrystal colloids were obtained in the nanometer scale (less than 10nm) and the crystallite size was smaller than pure TiO2. Anatase phase, mixture phase (anatase and rutile) and rutile phase of Sn-doped TiO2 samples were formed, when x <0.04, 0.04< x <0.06 and x ≥0.06, respectively. The Sn4+ dopants presented substitution Ti4+ into the lattice of TiO2 alongside increasing the surface oxygen vacancies and the surface hydroxyl groups. Regarding photocatalytic activity, Sn-doped TiO2 samples (TiSn3) were nearly four times higher than undoped samples. This obvious beneficial effect could be attributed to high surface area, optimal crystalline phase and surface state modifications. [ABSTRACT FROM AUTHOR]