Synthesis And Study On Properties For Bi-based Photocatalyst

As a solution to solve water pollution,photocatalytic technology has the characteristics of low energy consumption and environmental friendliness.The preparation of the catalyst with high performance is the core problem for it.The photocatalytic effect was observed in TiO2 originally.However,its practical application is restricted by some disadvantages of TiO2.Therefore,other semiconductors need to be studied.In this paper,a series of composites of Bi-based nanofibers were prepared by electrospinning and their photocatalytic properties were studied.The specific studies are as follows:(1)α-Bi2O3 nanofibers were prepared via electrospinning by using polyvinylpyrrolidone as template and bismuth nitrate as Bi source.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetric differential-thermal analysis(TG-DTA),ultraviolet-visible diffuse reflection spectrum(UV-vis DRS)and N2 adsorption desorption isotherm(BET),respectively.The photocatalytic properties of the prepared samples were evaluated by photocatalytic degradation of Rhodamine B(RhB),which were used as the degradation models.The extensibility of the catalyst was studied by using methylene blue,methyl orange,tetracycline and sulfampyridine.The results showed that the crystal structure of Bi2O3 samples were all monoclinic phase a-Bi2O3 after calcined the composite of fiber precursor PVP/Bi(NO3)3 at 450 ℃,500 ℃ and 550℃ in air atmosphere.In addition,the morphology of Bi2O3 samples were gradually changed from small diameter fiber(～100 nm)to crude(～150 nm),and finally broken into spherical particles at 550℃ with the increase of calcination temperature.It was also found that the Bi2O3 nanofibers obtained at 450℃ exhibit the excellent visible-light photocatalytic activity for the degradation of dye and antibiotic within 150 mins under Xe lamp(250 W)irradiation.The degradation of RhB,MB,MO,Tc and SASP was 98.4%,55.2%,71.9%,94.1%and 17.6%,respectively.(2)Using Bi(NO3)3·5H2O,NH4VO3,PVP as raw materials,the BiVO4/Bi2O3 nanofibers were successfully fabricated by electrospinning with a hydrothermal process.And the effects of the addition amount of BiVO4 obtained under different hydrothermal time,calcined temperature on the ratio of α-Bi2O3/β-Bi2O3 were studied.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),Ultraviolet-visible diffuse reflection spectrum(UV-vis DRS),N2 adsorption-desorption isotherm(BET)and photocurrent measurement.The photocatalytic properties of the as-prepared samples were evaluated by photocatalytic degradation of RhB served as the simulation contaminant.The results showed that BV06-3-45 had the best visible light catalytic activity,and the degradation rate of Rhodamine B reached 98.0%under Xenon lamp irradiation for 100 mins.The degradation of MB,MO,Tc,SASP and OTC was 69.2%,96.1%,81.5%,58.3%and 80.4%The catalyst keeps high degradation activity(93%)after 5 cycles,which indicating that the catalyst is stable.(3)CuBi2O4/Bi2O3 composite nanofibers were prepared via electrospinning.The effects of calcination temperature and the ratio of composite on their photocatalytic activity were studied.The samples were characterized by XRD,SEM,UV-vis DRS,TG-DTA,BET,EIS and photocurrent measurement.Sample obtained at 650℃,Rcu＝8 has the best visible light catalytic activity,and the degradation rate of MO reached 99.2%under the irradiation of Xe lamp for 100 minss.Under the same condition,the degradation rates of MB,RhB,Tc,SASP and OTC was 77.7%,57.3%,88.4%,30.0%and 70.0%,respectively.After 5 reuse,the degradation rate of MO is still over 90%,which indicating that the catalyst is stable.