二氧化锰/钒酸铋复合光催化剂的制备及性能
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摘要
采用液相沉淀法制备了不同锰含量的二氧化锰(MnO_2)/钒酸铋(BiVO_4)复合光催化剂,利用XRD、SEM、XPS等对催化剂进行了表征。通过对罗丹明B的降解,研究了不同锰含量的光催化剂在太阳光下的光催化降解性能,并考察了催化剂用量对光降解率的影响。结果表明,制备出的不同Mn含量的BiVO_4光催化剂均为单斜晶型结构,且Mn元素是以MnO_2的形式存在,说明Mn元素的引入没有改变BiVO_4的晶型和结构。其中Mn含量为1.67%的BiVO_4样品具有最高的光催化活性,光催化反应90 min对罗丹明B溶液的降解率可达到26.39%,比纯BiVO_4样品的降解率(14.06%)提高了近一倍,其催化性能提高的原因可能是由于一定量MnO_2的存在使催化剂中光生电子-空穴的高效分离造成的。同时发现当MnO_2的含量过高,由于形貌分布不均,会变成光生电子和空穴的复合中心,致使催化剂的活性降低。不同用量的同种催化剂光降解实验结果表明:对罗丹明B的光降解率随催化剂用量的增加而增大,但超过一定用量后,光降解率增加速度变缓。
Manganese dioxide(MnO_2)/bismuth vanadate(BiVO_4)composite photocatalysts with different manganese contents were prepared by simple liquid phase precipitation method,and the catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and X-ray photoelectron spectrometer(XPS).The photocatalytic performance of the BiVO_4 photocatalysts was evaluated by the degradation of rhodamine B in the sunlight,and the effect of catalyst dosage on photodegradation efficiency was investigated.The results show that the BiVO_4 photocatalysts with different Mn contents are monoclinal structure,and the Mn exsits in the form of MnO_2,indicating that the addition of Mn do not change the crystal and structure of BiVO_4.Among the catalysts,the BiVO_4 sample with 1.67%Mn content has the highest photocatalytic activity,and the degradation efficiency can reach 26.39%after 90 min photocatalytic reaction on rhodamine B solution,which improves nearly one time compared to that of the pure BiVO_4 sample(14.06%).The enhanced photocatalytic activity may be due to the efficient separation of electron-hole pairs with a certain amount of MnO_2.At the same time,it is found that when the content of MnO_2 is too high,it will become the composite center of photogenic electron and hole due to the uneven morphology,and the activity of the catalyst will be reduced.Photocatalytic experiments using different amounts of the same catalyst show that the photodegradation efficiency of rhodamine B increases with the increase of amounts of the catalyst,but after more than a certain amount,the photodegradation efficiency increases slowly.
Manganese dioxide(MnO_2)/bismuth vanadate(BiVO_4)composite photocatalysts with different manganese contents were prepared by simple liquid phase precipitation method,and the catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and X-ray photoelectron spectrometer(XPS).The photocatalytic performance of the BiVO_4 photocatalysts was evaluated by the degradation of rhodamine B in the sunlight,and the effect of catalyst dosage on photodegradation efficiency was investigated.The results show that the BiVO_4 photocatalysts with different Mn contents are monoclinal structure,and the Mn exsits in the form of MnO_2,indicating that the addition of Mn do not change the crystal and structure of BiVO_4.Among the catalysts,the BiVO_4 sample with 1.67%Mn content has the highest photocatalytic activity,and the degradation efficiency can reach 26.39%after 90 min photocatalytic reaction on rhodamine B solution,which improves nearly one time compared to that of the pure BiVO_4 sample(14.06%).The enhanced photocatalytic activity may be due to the efficient separation of electron-hole pairs with a certain amount of MnO_2.At the same time,it is found that when the content of MnO_2 is too high,it will become the composite center of photogenic electron and hole due to the uneven morphology,and the activity of the catalyst will be reduced.Photocatalytic experiments using different amounts of the same catalyst show that the photodegradation efficiency of rhodamine B increases with the increase of amounts of the catalyst,but after more than a certain amount,the photodegradation efficiency increases slowly.
引文
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[2]Hirakawa H,Shiota S,Shiraishi Y,et al.Au nanoparticles supported on BiVO4:effective inorganic photocatalysts for H2O2 production from water and O2 under visible light[J].ACS Catalysis,2016,6(8):4976-4982.
[3]Regmi C,Kshetri Y K,Kim T H,et al.Visible-light-induced Fe-doped BiVO4,photocatalyst for contaminated water treatment[J].Molecular Catalysis,2017,432(9):220-231.
[4]Wang M,Liu Q,Che Y,et al.Characterization and photocatalytic properties of N-doped BiVO4,synthesized via a sol–gel method[J].Journal of Alloys&Compounds,2013,548(10):70-76.
[5]Wang M,Yang G,You M,et al.Effects of Ni doping contents on photocatalytic activity of B-BiVO4,synthesized through sol-gel and impregnation two-step method[J].Transactions of Nonferrous Metals Society of China,2017,27(9):2022-2030.
[6]Nanakkal A R,Alexander L K.Graphene/BiVO4/TiO2,nanocomposite:tuning band gap energies for superior photocatalytic activity under visible light[J].Journal of Materials Science,2017,52(13):7997-8006.
[7]Sun J,Li X,Zhao Q,et al.Novel V2O5/BiVO4/TiO2 nanocomposites with high visible-light-induced photocatalytic activity for the degradation of toluene[J].Journal of Physical Chemistry C,2014,118(19):10113-10121.
[8]Ju P,Wang P,Li B,et al.A novel calcined Bi2WO6/BiVO4 heterojunction photocatalyst with highly enhanced photocatalytic activity[J].Chemical Engineering Journal,2014,236(2):430-437.
[9]Chen F,Yang Q,Li X,et al.Hierarchical assembly of graphene-bridged Ag3PO4/Ag/BiVO4,(040)z-scheme photocatalyst:an efficient,sustainable and heterogeneous catalyst with enhanced visible-light photoactivity towards tetracycline degradation under visible light irradiation[J].Applied Catalysis B:Environmental,2017,200(1):330-342.
[10]Kanigaridou Y,Petala A,Frontistis Z,et al.Solar photocatalytic degradation of bisphenol A with CuOx/BiVO4:Insights into the unexpectedly favorable effect of bicarbonates[J].Chemical Engineering Journal,2017,318(12):39-49.
[11]Li H,Zhang J,Huang G,et al.Hydrothermal synthesis and enhanced photocatalytic activity of hierarchical flower-like Fe-doped BiVO4[J].Transactions of Nonferrous Metals Society of China,2017,27(4):868-875.
[12]Cao S,Yin Z,Barber J,et al.Preparation of Au-BiVO4 heterogeneous nanostructures as highly efficient visible-light photocatalysts[J].ACS Applied Materials&Interfaces,2012,4(1):418-423.
[13]Zhou B,Zhao X,Liu H,et al.Visible-light sensitive cobalt-doped BiVO4(Co-BiVO4)photocatalytic composites for the degradation of methylene blue dye in dilute aqueous solutions[J].Applied Catalysis B:Environmental,2010,99(1):214-221.
[14]Chen R,Wang W,Jiang D,et al.Hydrothermal synthesis of Nd3+-doped heterojunction ms/tz-BiVO4 and its enhanced photocatalytic performance[J].Journal of Physics and Chemistry of Solids,2018,117(6):28-35.
[15]Luo Y,Tan G,Dong G,et al.Effects of structure,morphology,and up-conversion on Nd-doped BiVO4 system with high photocatalytic activity[J].Ceramics International,2015,41(2):3259-3268.
[16]Wang M Che Y,Niu C,et al.Lanthanum and boron co-doped BiVO4 with enhanced visible light photocatalytic activity for degradation of methyl orange[J].Journal of Rare Earths,2013,31(9):878-884.
[17]Chen L,Meng D,Wu X,et al.In situ synthesis of V4+ and Ce3+ self-doped BiVO4/CeO2 heterostructured nanocomposites with high surface areas and enhanced visible light photocatalytic activity[J].The Journal of Physical Chemistry C,2016,120(33):18548-18559.
[18]Yang Y,Qiu L,Jacobson A J.Manganese doped bismuth vanadate solid electrolytes:oxygen permeation in Bi2V0.8Mn0.2O5.3[J].Journal of Materials Chemistry,1997,7(6):937-941.
[19]王敏,朱彤,吕春梅.钒酸铋光催化剂及其应用[M].北京:化学工业出版社,2017,41-44.
[20]戈磊,崔立山.新型可见光活性氧化钯/钒酸铋复合光催化剂的制备及其光催化性能[J].硅酸盐学报,2008,36(3):320-324.
[21]周慧,杜彬,陈丽萍.三种形貌BiVO4微纳材料的制备及其光催化性能研究[J].化学研究与应用,2016,28(10):1494-1499.
[22]苑丽质.La-TiO2/Hβ复合光催化剂降解模拟染料废水[J].化工新型材料,2015,43(4):247-249.