Search

Abstract: A series of dye-modified TiO2 photocatalysts were synthesized using dye Chrysoidine G (CG), tolylene-2,4-diisocyanate (TDI), and commercial TiO2 (Degussa P25) as starting materials. TDI was used as a bridging molecule whose two –NCO groups reacted with Ti–OH of TiO2 and –NH2 groups of CG, respectively. As a result, special organic complexes were formed on the TiO2 surface via stable π-conjugated chemical bonds between TiO2 and dye molecules, confirmed by FT-IR, XPS, and UV–vis spectra. Due to the existence of π-conjugated surface organic complexes, the as-synthesized photocatalysts showed a great improvement in visible absorption (400–550nm). Methylene blue, as a photodegradation target, was used to evaluate the photocatalytic performance, and the dye-modified TiO2 exhibited much better activity under the visible light irradiation than bare TiO2. [Copyright &y& Elsevier]

Abstract: A first-principles calculation based on the density functional theory (DFT) was used to investigate the energetic and electronic properties of Si-doped anatase TiO2 with various silicon concentrations. The theoretical calculations showed that with Si-doping the valence band and conduction band of TiO2 became hybrid ones with large dispersion, which could benefit the mobility of the photo-generated carriers. This result is in agreement with the experimental reports. At lower doping levels, the band gap of Si-doped anatase TiO2 decreases about 0.2eV. With the increase of silicon concentration, the band gap increases gradually and larger formation energies are required during the synthesis of Si-doped TiO2. [Copyright &y& Elsevier]