Preparation Of Silver Phosphate Composite Material And Its Photocatalytic Performance

In recent years, semiconductor photocatalyst has become a hot topic. The semiconductor photocatalyst with high efficiency, no secondary pollution and good stable, have been widely used in hydrogen production, wastewater treatment, air purification etc. Conventional catalysts such as TiO₂, ZnO can only absorb ultraviolet light, which do not take full use of the sunlight, so the researchers are focusing on the development of visible-light-photocatalyst. In the latest study, the silver-based catalyst, such as Ag₃PO₄, Ag3VO4, can absorb visible light and has high photocatalytic activity, so it is greatly concerned. In this paper, the visible-light-photocatalyst Ag₃PO₄ is studied, and it is modified by few-layer Mo S₂,CeO₂ and three-dimensional ordered macroporous WO₃（3 DOM WO₃） to improve the photocatalytic activity and stability of Ag₃PO₄. The X-ray diffraction（XRD）,transmission electron microscopy（TEM）, X-ray photoelectron spectroscopy（XPS）,Fourier transform infrared spectroscopy（FT-IR）, scanning electron microscopy（SEM）and diffuse reflection spectra（DRS） have been used to characterize structure,morphology, optical properties of the sample. The main contents of this paper are as follows:The few-layer Mo S₂/Ag₃PO₄ composites are fabricated by a sample precipitation method. The physical and chemical property of few-layer Mo S₂ photocatalyst are analyzed to investigate the effects of few-layer Mo S₂ on the photocatalytic activity of Ag₃PO₄. The photocatalytic activity of few-layer Mo S₂/Ag₃PO₄ composites is evaluated by the photocatalytic degradation of Rhodamine B（RhB） under visible light irradiation. The photocatalytic activity of the few-layer Mo S₂/Ag₃PO₄ composite is higher than that of pure Ag₃PO₄. The optimal few-layer Mo S₂ content for the photocatalytic activity of the heterojunction structures is 0.5 wt%. The photocatalytic degradation efficiency of RhB is 94.4% for few-layer Mo S₂/Ag₃PO₄（0.5 wt%） after irradiation for 12 min. Compared to the pure Ag₃PO₄, the photocatalytic degradationefficiency of few-layer Mo S₂/Ag₃PO₄（0.5 wt%） increase by 24%. The synergic effect between few-layer Mo S₂ and Ag₃PO₄ is found to lead to an improved photo-generated carrier separation, which increases the photocatalytic degradation efficiency of few-layer Mo S₂/Ag₃PO₄ composites. The stability and the possible photocatalytic mechanism of few-layer Mo S₂/Ag₃PO₄ composites are also discussed.The CeO₂/Ag₃PO₄ composite photocatalysts are synthesized by an in situ precipitation method. XRD, FT-IR, XPS, TEM and DRS have been used to characterize the structure of the sample. The photocatalytic performance of the prepared samples is evaluated by the photocatalytic degradation of methylene blue（MB） and ciprofloxacin（CIP）. The results show that CeO₂/Ag₃PO₄ hybrid materials exhibit much higher photocatalytic activity than the pure Ag₃PO₄. The optimal CeO₂ content in CeO₂/Ag₃PO₄ composites is found when the mass ratio is 1%. Photocurrent response of CeO₂/Ag₃PO₄（1 wt%） is about 1.5 times as high as than that of the pure Ag₃PO₄. The increase of photocatalytic activity of CeO₂/Ag₃PO₄ composites is mainly attributed to form heterojunction between CeO₂ and Ag₃PO₄, which promotes the separation of electrons and holes. The trapping experiment has demonstrated that holes serve as the main active species for degradation of MB under the visible light. It is discussed that CeO₂ content has an effect on the photocatalytic degradation efficiency of the CeO₂/Ag₃PO₄ hybrid materials. A Photocatalytic mechanism is also proposed.3 DOM WO₃ is successfully synthesized by using PMMA template, and 3 DOM WO₃/Ag₃PO₄ composite catalysts are prepared by situ precipitation method. The composites are characterized by XRD, SEM, TEM, XPS, DRS and FT-IR. Under visible light irradiation, the as-prepared 3 DOM WO₃/Ag₃PO₄ composites show enhanced photocatalytic performance for MB degradation. The sample with 3 DOM WO₃/Ag₃PO₄（4 wt%） exhibits the highest photocatalytic activity. The enhanced photocatalytic performance under visible light irradiation could be due to unique pore structure of WO₃ and a synergistic effect between 3 DOM WO₃ and Ag₃PO₄. Afterintroduction of 3 DOM WO₃, it could increase the separation efficiency of the photogenerated electron-hole pairs.