Bi2WO6/UiO-66复合材料的制备及其光催化性能

通过水热法制备了一种复合光催化剂Bi_2WO_6/UiO-66,探究了模板剂乙酸(CH_3COOH)对Ui O-66形貌的影响和2种中心元素Bi与Zr的不同物质的量之比对光催化性能的影响。通过XRD、SEM、N_2吸附-脱附、UV-Vis DRS、XPS等对催化剂的物相、形貌、比表面积、光吸收性能、元素组成等进行表征。实验结果表明,当n_(Bi)∶n_(Zr)=2∶1时,Bi_2WO_6/UiO-66对罗丹明B(RhB)的光催化活性最高,可见光照射50 min后,RhB的相对浓度降低98.5%。经过5次循环利用实验,催化剂的光催化活性没有明显下降,说明复合光催化剂的稳定性高。根据自由基捕获实验证明了空穴(h~+)为光催化中起决定性作用的活性物质,结合电化学测试以及UV-Vis DRS表征提出了可能的光催化降解机理。

Synthesis and Photocatalytic Properties of Bi2WO6/UiO-66 Composite

A composite photocatalyst Bi₂WO₆/UiO-66 was prepared by hydrothermal method. The effect of template glacial acetic acid (CH₃COOH) on the morphology of UiO-66 and the effects of different molar ratios of Bi and Zr on the photocatalytic performance of the composite were investigated. XRD, SEM, N₂ adsorption-desorption, UV-Vis DRS and XPS were used to characterize the phase, morphology, specific surface area, optical absorption performance and element composition of the catalyst. The experimental results show that when n_Bi:n_Zr=2:1, the photocatalytic activity of RhB by Bi₂WO₆/UiO-66 is the highest. The relative concentration of RhB decreased 98.5% after 50 minutes of visible light irradiation. After five recycling experiments, there was no significant decrease in photocatalytic activity, but the photocatalytic activity of pure Bi₂WO₆ decreased greatly, which indicated that the stability of the complex is higher than that of pure Bi₂WO₆. According to free radical trapping experiments, it is proved that holes (h⁺) play an important role in photocatalysis. The reasons for the improvement of photocatalytic activity were further explained by electrochemical test. The band gap and valence band position of the material were obtained by UV-Vis DRS and VB-XPS, and the possible photocatalysis mechanism was put forward.