The Research On Preparation, Characterization And Visible-Light Photocatalytic Performance Of Ag/AgCl Modified Nanocomposite Materials

Along with the development of global industrialization process, the global environment pollution and energy crisis become more and more serious. Environmental issues have already become one of the most important problem which influence human survival and development in 21 st century. Photocatalytic technology, as a member of advanced oxidation technology and a typical representative of green chemistry, has aroused tremendous interest. Ti O2, as a traditional photocatalyst, is widely used for its long-term stability, low cost, nontoxicity and availability. Ti O2 can be only excited by ultraviolet irradiation which is ⁴% UV light in solar irradiation due to the relatively wide band gap. For this reason, the wide use of Ti O2 is significantly limited in practical application. The Bi-based materials with characteristic structures of alternative stacking of?Bi2O2?2+ layers and slabs of other inorganic atoms or groups all belong to the layered or Aurivillius-related oxide family. Ag/Ag X is a novel kind of plasmonic photocatalyst, which combines the property of noble metal nanoparticles surface plasmon resonanc?SPR?, metal-semiconductor contact and semiconductor photocatalyst. Thus, there seems to be great untapped potential to explore the possibility of exploiting Ag/AgCl to help enhance photocatalytic performance. For Ag/AgCl/Bi2 Mo O6-9.5%, the corresponding degradation rate constant of Rh-B is up to 10-fold faster than that over Bi₂O₂CO₃. For Ag/AgCl/Bi₂O₂CO₃-4, the corresponding degradation rate constant of Rh-B is up to 10-fold faster than that over Bi₂O₂CO₃. The results indicate the excellent photocatalytic activities of hybrids are thanks to the introduction of Ag/AgCl nanoparticles.In this paper, Ag/AgCl nanoparticles were deposited on Bi₂O₂CO₃ and Bi2 Mo O6 substrate at room temperature via a precipitation-photoreduction reaction for the sake of extending the photoresponse of photocatalysts to the visible region. The samples were characterized by ICP?XRD?SEM?TEM?HRTEM?FT-IR?BET?UV-vis DRS.The main results of the present work were summarized as follows:1. The Ag/AgCl/Bi₂O₂CO₃ and Ag/AgCl/Bi2 Mo O6 composites show superior photocatalytic activities. The ratio of Ag: Bi was found to influence the photocatalytic performance of as-obtained product. 2. The photocatalytic performance of Ag/AgCl/Bi₂O₂CO₃ was evaluated through the degradation of rhodamine-B?Rh-B?, crystal violet?CV? and methyl orange?MO? aqueous solution under visible-light irradiation?? ? 420 nm?. 3. The photocatalytic activities of Ag/AgCl/Bi2 Mo O6 were measured through the decomposition of rhodamine-B?Rh-B? and methyl orange?MO? aqueous solution under visible-light irradiation?? ? 420 nm?. 4. On the basis of band structure analysis and active species trapping experimental results, different photocatalytic mechanisms are proposed. A surface plasmon resonance?SPR? mechanism is put forward to explain the enhanced photocatalytic performance of Ag/AgCl/Bi₂O₂CO₃. The plasmonic Z-scheme photocatalytic mechanism is proposed to explain the enhanced photocatalytic performance of Ag/AgCl/Bi2 Mo O6 composites. The active species in Rh-B degradation over Ag/AgCl/Bi₂O₂CO₃ are found to be h+ and ?O2-. h+, ?OH and ?O2- as the significant active species are generated and act as main reactive species for Ag/AgCl/Bi2 Mo O6 in the photocatalytic degradation instead of ?OH.