橄榄状BiVO<sub>4</sub>的制备及其可见光催化性能研究

Abstract

本文以柠檬酸钠为络合剂，丙二酸为形貌控制剂，通过一步水热法制备了橄榄状BiVO4光催化剂。采用X-射线衍射(XRD)、扫描电子显微镜(SEM)以及紫外–可见漫反射(UV-Vis DRS)对材料的晶型、形貌以及吸收光谱进行表征，并以罗丹明B(RhB)为模拟降解污染物，测试BiVO4的可见光催化活性。结果表明：所制备的样品纯度高，为单斜晶相BiVO4，柠檬酸钠及丙二酸都对材料的形貌产生重要的影响。合成出的橄榄状BiVO4具有很强的可见光吸收能力，禁带宽度为2.36 eV，表现出最强的光催化活性。在500 W的氙灯激发下，2 h后，对罗丹明的降解率达到94%，并且所制备的样品具有良好的抗光腐蚀性，三次循环降解后，仍保持了92%的降解率。 Olive-like BiVO4 crystals were synthesized via a one-step hydrothermal method by using sodium citrate as the chelating agent and propane diacid as the shape control agent. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible diffuse reflectance spectrum (UV-Vis DRS) were employed to elucidate the structures, morphologies and the light absorption properties of the as-prepared BiVO4 samples. The photo-catalytic activities of BiVO4 crystals were evaluated by using rhodamine B (RhB) as simulative degradation pollutant. The results showed that all the samples possessed monoclinic structure and containing no any impurities. Both sodium citrate and propane acid have great influence on the morphologies of BiVO4 samples. The as-prepared olive-like BiVO4 samples had strong visible-light absorption abilities with the band gap value around 2.36 eV, and showed the highest photo-catalytic activities. The degradation rate of RhB could reach 94% after 2 h of irradiation with a 500 W Xe-illuminator. After three cycles of photo-catalytic degradation experiments, degradation rate still maintained 92%, which indicated that the olive-like samples had good resistant abilities to photocorrosion.