Oxygen vacancies in crystal have important impacts on the electronic properties of ZnO. With ZnO(2) as precursors, we introduce a high concentration of oxygen vacancies into ZnO successfully. The obtained ZnO exhibits a yellow color, and the absorption edge shifts to longer wavelength. Raman and XPS spectra reveal that the concentration of oxygen vacancies in the ZnO decreased when the samples are annealed at higher temperature in air. It is consistent with the theory calculation. The increasing of oxygen vacancies results in a narrowing bandgap and increases the visible light absorption of the ZnO. The narrowing bandgap can be confirmed by the enhancement of the photocurrent response when the ZnO was irradiated with visible light. The ZnO with oxygen vacancies are found to be efficient for photodecomposition of 2,4-dichlorophenol under visible light irradiation.

A facile and efficient photoreduction method is employed to synthesize the composite of methylammonium lead iodide perovskite (MAPbI ) with reduced graphene oxide (rGO). This MAPbI /rGO composite is shown to be an outstanding visible-light photocatalyst for H evolution in aqueous HI solution saturated with MAPbI . Powder samples of MAPbI /rGO (100 mg) show a H evolution rate of 93.9 µmol h , which is 67 times faster than that of pristine MAPbI , under 120 mW cm visible-light (λ ≥ 420 nm) illumination, and the composite is highly stable showing no significant decrease in the catalytic activity after 200 h (i.e., 20 cycles) of repeated H evolution experiments. The electrochemiluminescence performance of MAPbI is investigated to explore the charge transfer process, to find that the photogenerated electrons in MAPbI are transferred to the rGO sites, where protons are reduced to H .

Cu 2 O microcrystals with well-formed facets were synthesized by a simple hydrothermal method. The surface stabilities and photocatalytic properties of Cu 2 O microcrystals were systematically investigated. Cu 2 O {100} and {110} facets gradually disappear and transform into nanosheets during the photodegradation of methyl orange (MO) dye. With the increase of irradiation time, Cu 2 O microcrystals completely transform into nanosheets with {111} facets. The finally formed nanosheets exhibit stable photocatalytic activities. On the basis of both experimental analysis and theoretical calculations, a novel model of charge separation among crystal faces was proposed and the morphology transformation mechanism accompanied by MO bleaching was discussed. It is concluded that Cu 2 O exposing {111} facets can be used as a stable photocatalyst.

Visible improvements: Owing to the plasmon resonance of silver nanoparticles deposited on the surface of AgBr, the newly-prepared plasmonic photocatalyst Ag section signAgBr has a strong absorption in the visible region (see picture) and shows high efficiency in the photodegradation of organic pollutants under visible light.

Surface-hydrogenated anatase TiO(2) (TiO(2)-H) nanowire-microspheres were prepared by converting protonated titanate nanotube to TiO(2)-H under a hydrogen atmosphere. We show that TiO(2)-H nanowire-microspheres have Ti-H and O-H bonds on their surface and exhibit improved visible-light absorption and highly enhanced photocatalytic activity.