Synthesis And Photocatalytic Properties Of Bi 4 Ti 3 O 12 Based Materials

Bi₄Ti₃O₁₂ is a new kind of photocatalytic materials with bismuth layered perovskite structure,the crystal?Bi2Ti3O10?2-and?Bi2O2?2+ layer will form an electric field,then it is conducive to the separation of photogenerated electron hole pairs,which has excellent photocatalytic properties.In this paper,the pure phase Bi₄Ti₃O₁₂ lamellar nanostructures was synthesized by molten salt method,using Bi2O3 and TiO2 as raw materials,the NaCl?KCl as molten salt agent.The Bi2Tii2O7Bi₄Ti₃O₁₂ composite photocatalysts were synthesized by adjusting the Bi/Ti molar ratio of raw materials.The CeCO2Bi₄Ti₃O₁₂ composite photocatalysts were synthesized by thermal decomposition method,using CeNO3)3·6H2O as the cerium source.Fe-doped Bi₄Ti₃O₁₂ nanosheets were synthesized by molten salt method,using Fe2O3 as a source of iron.Au nanoparticles were loaded on Fe-doped Bi₄Ti₃O₁₂ nanosheets via a room-temperature hydrogen peroxide reduction method.The phase structure,morphology,and optical property of the samples were characterized by XRD,XPS,SEM,EDS Mapping,TEM,BET,UV-vis spectroscopy,respectively.The photocatalytic performances of the samples were evaluated by the degradation of cationic Rhodamine B?RhB??anionic methyl orange?MO?,and non dye type phenol and bisphenol A solution under light irradiation.The main work of this paper is as follows:?1?The Bi2Ti2O7/Bi₄Ti₃O₁₂ composite photocatalysts were synthesized by a one-step molten salt method.The results of SEM,EDS and TEM shows that the sub-micron-sized particles of Bi2Ti2O7 were successfully formed a composite structure with the sheets of Bi₄Ti₃O₁₂.Compared with pure Bi₄Ti₃O₁₂,the as-prepared Bi2Ti2O7/Bi₄Ti₃O₁₂ composite?for the Bi/Ti ratio?4:3.2?exhibit more excellent photocatalytic activities in the degradation of methyl orange?MO?and Rhodamine B?RhB?in aqueous solutions under simulated solar light irradiation.The photodegradation rates of MO?10 mg/L?and RhB?10 mg/L?is 99.1%and 99.5%,respectively.?2?In order to further improve the photocatalytic activity of the B14T13O12 photocatalyst,the CeO2/Bi₄Ti₃O₁₂ composite heterojunction photocatalysts was synthesized by molten salt method and ion-impregnation method,using CeNO3)3·6H2O as the cerium source.The composite amount of CeO2 is 0.5wt%,1wt%,2wt%and 3wt%,respectively.The crystal structure and morphology of synthetic samples were characterized by XRD,XPS,SEM,EDS Mapping,TEM,BET,UV-vis spectroscopy,and M-S,respectively.To consider the pollutant issues,bisphenol A?BPA?was applied to investigate the photocatalytic activity of the CeO2/Bi₄Ti₃O₁₂ composite photocatalysts under light irradiation.Our results show that lwt%CeO2/Bi₄Ti₃O₁₂ composite exhibits the highest photocatalytic activity for the degradation of BPA.Under the same experimental conditions,after 60 min light irradiation,the photodegradation rates of BPA with lwt%CeO2/Bi₄Ti₃O₁₂ composite photocatalysts is 96.8%.The effect of the initial pH value on the BPA photocatalytic degradation were studied over lwt%CeO2/Bi₄Ti₃O₁₂ sample.Compared with acidic environment,the neutral and weak alkaline reaction solution are more beneficial for the degradation of BPA over 1wt%CeO2/Bi₄Ti₃O₁₂ samples.?3?The Fe-doped Bi₄Ti₃O₁₂ nanosheets with exposed {001} facets were synthesized by molten salt method.The doping content of iron ion was 2mol%,4mol%and 6mol%,respectively.Au nanoparticles with a diameter range of 20-50 nm were loaded on 2%Fe-doped Bi₄Ti₃O₁₂ nanosheets via a room-temperature hydrogen peroxide reduction method.The crystal structure and morphology of synthetic samples were characterized by XRD,XPS,SEM,EDS Mapping,TEM,BET,UV-vis spectroscopy,respectively.Phenol and bisphenol A solutions were chosen as model organic pollutants to verify the influence of Fe3+-doping and plasmonic effect of Au nanoparticles on the photocatalytic activity of the catalyst.The Au-2%Fe/BTO sample exhibited the highest photocatalytic activity compared with other samples.