| With the environmental problems and energy crisis, photocatalysis has drawn extensive attention in the scientific world. This paper focused on two kinds of Ag-based photocatalysts, which are Ag3PO4 and Ag2CO3. The relationship between the morphological or structural characteristics and the photocatalytic properties was studied. The room temperature solid state method was developed to synthesize Ag3PO4 photocatalyst in industrial production. It was found that the morphology of as-prepared Ag2CO3 could be manipulated by varying the conditions of surfactants assisted process. Furthermore, the p-n heteroj unction was fabricated for facilitating the separation of photogenerated electron-hole pairs in order to improve the photocatalytic activity. The composition, morphology and optical properties of the materials were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis absorption spectrum. The photocatalyitc properties of these photocatalysts were futher investigated by the photodegradation of the model pollutant methylene blue (MB) and methyl orange (MO) under visible light. The details include:(1) Ag3PO4 microcrystals with highly enhanced visible light photocatalytic activity have been prepared by a facile, simple room temperature solid state reaction which is easy to produce materials in large scale. The photocatalytic properties of Ag3PO4 were investigated by the degradation of both methylene blue (MB) and methyl orange (MO) dyes under visible light irradiation. The as-prepared Ag3PO4 microcrystals exhibit highly and universally efficient ability for the degradation of organic pollutants.(2) Surfactants assisted method was used to control the morphology of Ag2CO3. Two-dimensional nanoplate and snowflake of Ag2CO3 photocatalysts were synthesized. The feeding order is extremely important to decide the morphology of Ag2CO3 in the presence of PEG 20000.(3) The p-n junction Ag2CO3/Ag2O photocatalysts for enhancement of visible-light photocatalytic properties have been successfully prepared through a photolysis method. Nano scale Ag2O particles were distributed on the surface of Ag2CO3. The photocatalytic properties of the samples were further investigated by the degradation of methyl orange (MO) under visible light irradiation. The experimental results reveal that the p-n junction Ag2CO3/Ag2O photocatalyst exhibits much higher visible-light photocatalytic acitivities than the individual Ag2CO3 for the degradation of methyl orange. The enhanced photocatalytic efficiencies are attributed to the charge transfer between n-type Ag2CO3 and the p-type Ag2O, which reduces the recombination of electrons and holes. After being exposed under visible light for 80 min,86% of MO was degraded by the Ag2CO3/Ag2O photocatalyst, while 51% of MO was degraded by the Ag2CO3. |
