ZnS/BiVO_(4)纳米复合材料的制备及其光催化性能研究

Preparation of ZnS/BiVO_(4)nanocomposites and study on their photocatalytic performance

以BiVO_(4)纳米棒为载体,采用室温共沉淀法制备了BiVO_(4)负载ZnS量子点的纳米复合材料,利用SEM、TEM、XRD和FT-IR等对其组成、结构、形貌进行表征;以四环素(TC)为污染物,考察了ZnS/BiVO_(4)复合材料的光催化性能。结果表明,与纯ZnS和BiVO_(4)相比,ZnS/BiVO_(4)复合材料对TC光催化降解的性能显著增强,其中,Zn/Bi摩尔比为2/1的ZnS/BiVO_(4)-2/1样品对TC的降解效果最佳,1 h内TC(20 mg/L)清除率达到83.5%。自由基猝灭实验证实光生空穴(h^(+))、超氧自由基(·O_(2)^(-))及羟基自由基(·OH)均在ZnS/BiVO_(4)-2/1样品光催化降解TC过程中发挥作用,初步阐述了ZnS/BiVO_(4)-2/1光催化TC降解的Z型异质结机理。

A series of BiVO_(4)loaded ZnS quantum dots nanocomposites are prepared with BiVO_(4)nanorods as carriers through co-precipitation method at room temperature,and their composition,structure,and morphology are characterized by means of SEM,TEM,XRD,and FT-IR.Taking tetracycline(TC)as a targeted pollutant,the photocatalytic performance of ZnS/BiVO_(4)nanocomposites is evaluated.Compared with pure ZnS or BiVO_(4),ZnS/BiVO_(4)composites show a significantly enhanced photocatalytic performance for tetracycline degradation.Among them,ZnS/BiVO_(4)-2/1 sample with a Zn/Bi molar ratio of 2/1 demonstrates the best photocatalytic performance for tetracycline degradation,over which more than 83.5%of tetracycline is removed within 60 min under the optimum conditions.It is confirmed through free radicals quenching experiment that photo generated holes(h^(+)),superoxide radicals(·O_(2)^(-)),and hydroxyl radicals(·OH)all play significant roles during the photocatalytic degradation process of tetracycline.A Z-type heterojunction mechanism is proposed for expounding ZnS/BiVO_(4)-2/1 photocatalytic performance in degradation of tetracycline.