二氧化锰/钒酸铋复合光催化剂的制备及性能  

Preparation and performance of manganese dioxide/bismuth vanadate composite photocatalysts

作　　者：刘景景 LIU Jing-jing(College of Vanadium and Titanium,Panzhihua University,Panzhihua 617000,China)

机构地区：[1]攀枝花学院钒钛学院,四川攀枝花617000

出　　处：《化学研究与应用》2019年第4期644-651,共8页Chemical Research and Application

基　　金：国家自然科学基金项目(51174122)资助

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.

关 键 词：钒酸铋 锰 光催化 降解 液相沉淀 

分 类 号：O614.51[理学—无机化学]