Preparation Of Apoferritin With FeOOH?Pb Se?CuSe Nanocomposites And Their Photocatalytic Properties

The widespread use of methyl orange dye,a type of azo dye,can cause serious pollution to water sources in nature.Therefore,there is a need to investigate an efficient,inexpensive and green material to treat printing and dyeing wastewater containing methyl orange.Photocatalysis is a green technology with important application prospects in energy and environment,especially semiconductor photocatalysts,which have become a hot research topic for many researchers because of its higher efficiency of sunlight utilization and simpler preparation method.However,existing semiconductor catalysts generally suffer from low solar light utilization efficiency and high complexation rate of photogenerated electrons and holes,so new catalyst materials need to be developed.PbSe and Cu Se narrow bandgap semiconductor materials have attracted a lot of attention because of their unique physical and chemical properties.In this paper,a class of highly efficient,green and stable semiconductor photocatalysts were prepared by combining apoferritin and nano-metal compounds,and these materials were used to degrade methyl orange dye in wastewater,and their degradation effects,the effect of p H and H₂O₂ concentration on degradation efficiency,and the kinetics and photocatalytic mechanism of catalytic degradation of methyl orange were investigated.The main contents and findings of the study are as follows:(1)Using apoferritin as a template to explore the conditions for preparing nanosemiconductors inside it,the results show that when there is apoferritin in solution with Pb²⁺(or Cu²⁺)together at room temperature,ammonium acetate is needed to stabilize the metal cation,and selenourea is added to the solution as a selenium source to slowly release Se^2-into the solution,so that it can be combined with the metal cation Pb²⁺(or Cu²⁺)to finally form monodisperse apo/PbSe(apo/Cu Se)nanosemiconductor materials.(2)The apoferritin/ferric oxyhydroxide(apo/FeOOH)materials were prepared by the template synthesis method,and the apoferritin/lead selenide(apo/PbSe)materials and apoferritin/copper selenide(apo/Cu Se)materials were prepared by the template synthesis method and two-step method.The basic properties of the synthesized materials were characterized using TEM,XRD,EDS,Uv-vis,PL,etc.The results showed that the size homogeneous and monodisperse apo/FeOOH composites,apo/PbSe composites and apo/Cu Se composites were successfully prepared.Calculation of the band gaps of the composites revealed that the resulting apo/FeOOH has a band width of 2.2 e V,apo/PbSe has a band width of about 1.35 e V,and apo/Cu Se has a band width of 1.4 e V,all of which are narrow band gap semiconductor materials.(3)The prepared composites were used for the photocatalytic degradation of methyl orange in water,respectively,and their photocatalytic degradation efficiency,conditions affecting the degradation efficiency of the catalyst,catalytic kinetics,catalytic mechanism and stability of the catalyst were investigated.The results showed that the efficiency of apo/FeOOH catalytic degradation of methyl orange was as high as 98.43%at 45 min of visible irradiation,p H=6.0 and 9%of H₂O₂ concentration;the efficiency of apo/PbSe degradation of methyl orange was up to 97.10%at 45 min of visible irradiation,p H=3.0 and 9%of H₂O₂ concentration,and the efficiency of apo/Cu Se degradation efficiency of methyl orange could reach 97.87%(both the amount of catalyst added was 0.15 mg and methyl orange concentration was 10 mg/m L),and the catalyst materials were able to maintain good stability after five cycles of experiments.The free radical capture experiments were conducted to investigate the photocatalytic degradation of methyl orange by the composites and to determine the mechanism of their photocatalytic degradation of methyl orange,respectively.