Papers by Keyword: Visible Light Photocatalyst

Abstract: Nanostructured AgBr/TiO2 visible light photocatalyst was prepared through deposition-precipitation method with AgNO3, KBr and Ti(OBu )4 as the precursors. Though the photocatalyst showed a relatively high photocatalytic efficiency for degradation of methyl orange in water under visible light irradiation in the first cycle, its efficiency was obviously decreased in the subsequent cycles. X-ray diffraction indicated that there existed a dramatic crystalline growth of AgBr in the AgBr /TiO2 nanocomposite after visible light irradiation, which must increase the recombination rate of photo-generated electrons and holes and be responsible for the observed decrease in photocatalytic efficiency. Photo-induced crystalline growth of AgBr may be a limiting factor for the lifetime of AgBr/TiO2 visible light photocatalyst and more attention should be paid to it.

Abstract: Monoclinic scheelite BiVO4 was synthesized from a mixture of aqueous Bi(NO3)3 and NH4VO3 solutions by hydrothermal method. Then using successive coating of BiVO4 with a carbon layer and a ZrO2 layer followed by heat treatment to remove the carbon layer prepared a core-shell(ZrO2@void@BiVO4) nanoparticles with a void layer between the BiVO4 core and the ZrO2 shell. TG-DTA and IR suggest that BiVO4 was coated with ZrO2. TEM shows that there was a void space between the BiVO4 core and the ZrO2 shell. The samples were characterized by XRD and the peaks of ZrO2@void@BiVO4 suits well with the pure phase monoclinic scheelite BiVO4. And its visble-light photocatalytic activity was evaluated by the photodegradation of methylene blue(MB). The results indicated that the photocatalytic activity of ZrO2@void@BiVO4 is similar to that of pure phase BiVO4, which makes it can be used for preparing liquid-gas phase boundary visble-light photocatalyst.

Abstract: Niobium and nitrogen co-doped SrTiO3 possessing excellent visible light responsive photocatalytic activity was successfully synthesized by microwave-assisted solvothermal reaction using SrCl2.6H2O, Ti(OC3H7)4, NbCl5 and hexamethylenetetramine in KOH aqueous solution. The photocatalytic activity was determined by DeNOx ability using LED lamps with the wavelengths of 627 nm (red), 530 nm (green), 445 nm (blue) and 390 nm (UV). The photocatalytic activity of SrTiO3 for DeNOx ability in visible light region could be improved by co-doping Nb5+ and N3-. The excellent visible light photocatalytic activity of this substance may be due to the generation of a new band gap that enables to absorb visible light and decrease in the lattice defects which acts as a recombination center of photoinduced electrons and holes.