Tb改性BiVO_(4)/BiOCl复合光催化剂的制备及性能研究  

Synthesis and properties of Tb modified BiVO_(4)/BiOCl composite photocatalysts

作　　者：刘景景 张泽兰 赵伟 Liu Jingjing;Zhang Zelan;Zhao Wei(College of Vanadium and Titanium,Panzhihua University,Panzhihua 617000,Sichuan,China)

机构地区：[1]攀枝花学院钒钛学院,四川攀枝花617000

出　　处：《钢铁钒钛》2021年第4期39-46,共8页Iron Steel Vanadium Titanium

基　　金：四川省大学生创新创业训练计划项目(其他);攀枝花学院大学生创新创业训练计划项目(其他)。

摘　　要：采用液相沉淀法制备了不同Tb含量的BiVO_(4)/BiOCl复合光催化剂,利用XRD、EDS等对催化剂进行了表征。以罗丹明B为目标降解污染物,采用单因素试验研究了Tb含量、光催化时间、催化剂用量、罗丹明B浓度等因素对样品光降解率的影响,并采用正交试验确定出最优方案。结果表明,纯钒酸铋为单斜晶型BiVO_(4);Tb含量为2%、4%的样品是单斜BiVO_(4)/BiOCl混合相;Tb含量为6%~12%的样品是单斜相BiVO_(4)/四方相BiVO_(4)/BiOCl混合相,这说明引入稀土Tb能够促使BiVO_(4)由单斜相转化为四方相。与纯BiVO_(4)相比,所有含Tb的BiVO_(4)样品的光降解率显著提高,且Tb元素的最佳含量(摩尔分数)为10%。在罗丹明B浓度为5 mg/L,催化剂用量为25 mg,光催化时间为2 h时,10%样品的光降解率高达100%,其光催化性能提高的原因可归因于稀土Tb的电子捕获效应以及形成的单斜相BiVO_(4)/四方相BiVO_(4)/BiOCl混相p-n异质结,有效提高了光生载流子的分离与传输,大大降低了电子-空穴对的复合,在污染废水处理方面具有极大的潜力和应用价值。BiVO_(4)/BiOCl composite photocatalysts with different contents of Tb were prepared by liquid phase precipitation method,and the catalysts were characterized by XRD and EDS.The photocatalytic performance of the photocatalysts was evaluated by degradation of rhodamine B under irradiation of the simulated sunlight.The effects of Tb content,photocatalytic time,catalyst dosage,rhodamine B concentration on the photodegradation efficiency of the samples were studied by single factor experiments,and the optimal scheme was determined by orthogonal tests.The results show that the pure BiVO_(4)belongs to monoclinic phase,and the samples with Tb content of 2%and 4%are mixture of monoclinic BiVO_(4)/BiOCl phases.The samples with Tb content of 6%~12%are mixture of monoclinic BiVO_(4)/tetragonal BiVO_(4)/BiOCl phases.It indicates that the introduction of Tb can promote the transformation of BiVO_(4)from monoclinic phase to tetragonal phase.Compared with that of the pure BiVO_(4),the photodegradation efficiency of all samples containing Tb is improved greatly,and the optimal molar fraction of Tb is 10%.At the rhodamine B concentration of 5 mg/L,the catalyst dosage of 25 mg,and the photocatalytic time of 2 h,the photodegradation efficiency of the sample with 10%Tb can reach100%.The improved photocatalytic performance may be attributed to the electron capture effect of Tb and the formation of monoclinic BiVO_(4)/tetragonal BiVO_(4)/BiOCl miscible p-n heterostructures,which effectively improve the separation and transmission of photoinduced carriers and suppress the recombination of electron-hole pairs.It has great potential and application value in the treatment of polluted wastewater.

关 键 词：BiVO_(4) TB 光催化 降解 液相沉淀 

分 类 号：TF841.3[冶金工程—有色金属冶金] TQ426[化学工程]