Preparation Of Fe₃O₄/Ag/Bi₂MoO₆ And Broad-spectrum Response Photocatalysis-Fenton Coupling Catalytic Application Research

Photocatalysis,as one of the most promising environmentally friendly technology,is widely used in the degradation of environmental pollutants.Bi₂MoO₆,as a n-type semiconductor and a typical Aurivillius oxide,is a promising visible light-driven photocatalyst because of its narrow band gap of².5 eV and its suitable conduct band/valance band?CB/VB?edge positions.However,a drawback of Bi₂MoO₆ is the low quantum yield,which is caused by the rapid recombination of photogenerated electron-hole pairs,limiting its practical application.The doping of noble metals and the construction of heterojunctions are effective methods to solve the shortcoming of rapid recombination of photogenerated electron-hole pairs.When the plasma photocatalyst is irradiated by visible light or near infrared,due to LSPR,"hot electrons"are overflowed from Ag,which promote to the photocatalytic activity for protons reduction by advantage of the neighboring Bi₂MoO₆ that possesses abundant hydrogen active sites and high charge mobility.However,the photocatalytic performance of the isolated photocatalytic system is still unsatisfactory for practical applications.Fenton technology,which has been widely used in many wastewater treatment,is introduced as another way to eliminate pollutants.The principle of Fenton reaction is to oxidize organic compounds,such as carboxylic acids,alcohols,esters,and so on,to inorganic state by the mixture of H₂O₂ and Fe²⁺.The mixed solution of H₂O₂ and Fe²⁺has strong oxidation property.Magnetite,as a member of Fenton catalysts,has attracted a great attention.Fe₃O₄ contains Fe²⁺cation,which has higher decomposition ability than Fe³⁺on the effect of H₂O₂.In this paper,Ag/Bi₂MoO₆ and Fe₃O₄/Ag/Bi₂MoO₆ composite photocatalysts were prepared.The prepared samples were characterized by XRD,XPS,UV-vis,SEM,TEM and so on.Bisphenol A?BPA?and Aatrex were used as the target organic pollutants for photocatalytic degradation.The research results include:?1?Bi₂MoO₆ layered microspheres were successfully synthesized by solvothermal method using bismuth nitrate and sodium molybdate as precursors.Bi₂MoO₆ layered microspheres were prepared by calcination at 400 ^oC with a heating rate of 2 ^oC min^-1for 3 hours.Silver nitrate dripped into Bi₂MoO₆ solution was reduced to Ag by light reduction and deposited on the surface of Bi₂MoO₆ layered microspheres.The synthesized binary composite photocatalyst exhibited strong photocatalytic activity.The degradation rates of BPA and Aatrex were 54.3%and 60.5%,respectively.?2?Fe₃O₄/Ag/Bi₂MoO₆ ternary composite photocatalyst was synthesized by hydrothermal method by adding Ag/Bi₂MoO₆ layered microspheres into the mixed solution of ferric chloride,sodium acetate and sodium hydroxide.The introduction of Fe₃O₄ and Ag not only solves the inherent defects of single semiconductor photocatalyst,but also introduces Fenton advanced oxidation technology and plasma resonance technology to improve the degradation performance of the final photocatalyst for high toxic organic pollutants.Under simulated solar irradiation,the degradation rates of BPA and Aatrex in the final sample Fe₃O₄/Ag/Bi₂MoO₆ were 98.9%and 99.2%,respectively.