可见光驱动Bi_(2)WO_(6)/g-C_(3)N_(4)活化过硫酸盐降解罗丹明B

Degradation of Rhodamine B by Bi_(2)WO_(6)/g-C_(3)N_(4) activated persulfate under visible light irradiation

采用水热法和高温煅烧法制备了钨酸铋/石墨氮化碳(Bi_(2)WO_(6)/g-C_(3)N_(4),BWC),通过XRD、SEM、FT-IR、UV-vis DRS对其形貌结构和性质进行表征,研究可见光照射下BWC活化过硫酸盐(persulfate,PS)降解罗丹明B(Rhodamine B,RhB)的效果和机制。结果表明:BWC光吸收边缘红移至472nm,禁带宽度减小至2.50eV,g-C_(3)N_(4)可以增强Bi_(2)WO_(6)在可见光驱动下活化PS降解RhB的能力;反应60 min时,RhB降解率达98.66%,降解速率为0.0593 min^(-1);经过4次循环后,BWC对RhB仍有良好的降解效果,稳定性较好,可重复使用;活性物质捕获实验表明体系中反映的主要活性物质为空穴(h^(+))、超氧自由基(·O_(2)^(-))和单线态氧(^(1)O_(2));进一步分析Mott-Schottky(M-S)曲线提出BWC光生载流子的转移为Z型异质结机制。

In this paper,Bi_(2)WO_(6)/g-C_(3)N_(4)(BWC)was prepared by hydrothermal method and hightemperature calcination method.The morphology,structure and properties were characterized by X-ray diffractometer(XRD),scanning electron microscope(SEM),fourier transform infrared spectrometer(FT-IR),UV-vis diffuse reflectance specatrum(UV-vis DRS).The effect and mechanism of degradation of Rhodamine B(RhB)by BWC activated persulfate(PS)under visible light irradiation were studied.The results showed that the light absorption edge of BWC red shifts to 472 nm,the band gap decreas to 2.50 eV.g-C_(3)N_(4)could enhance the ability of Bi_(2)WO_(6) to activate PS under visible light to degrade RhB.The degradation rate of RhB reached 98.66% and the degradation rate was 0.0593 min^(-1)after 60 min of reaction;After 4 cycles,BWC still has a good degradation effect on RhB,has good stability and can be reused;The active substance capture experiment shows that the main active substances reflected in the system are holes(h^(+)),superoxide radicals(·O_(2)^(-)),and singlet oxygen(^(1)O_(2));Further analyzing of the Mott-Schottky(M-S)curve suggests that the transfer of BWC photogenerated carriers is a Z-type heterojunction mechanism.