Co-BiVO4异质结光催化剂的制备及其性能

摘要

采用一步水热法合成具有高效光催化活性的Co-BiVO4纳米复合材料.该材料通过Co氧化物包覆在钒酸铋表面构成p-n型异质结结构.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、高倍透射电镜(HRTEM)、X射线光电子能谱(XPS)、紫外可见漫反射(UV-visDRS)等对所制备的纳米光催化剂进行形貌、结构、组成及光电性能表征分析.发现Co是以氧化物的形式负载在BiVO4的表面,并且复合材料的可见光吸收带发生了红移.利用亚甲基蓝(MB)作为目标污染物,以可见光作为光源考察不同材料的光催化性能.结果表明,Co-BiVO4复合光催化剂的催化活性明显高于纯BiVO4.当Bi和Co的复合比为2:1时,Co-BiVO4的光催化活性最高,与纯BiVO4相比光催化反应速率提高了4倍.本研究完善了铋系异质结和过渡金属提高光催化活性的相关机理.%A unique Co-BiVO4 photocatalyst with heterostructure was synthesized via a simple one-step hydrothermal method. The material forms a p-n-type heterojunction structure by coating cobalt oxide on the surface of BiVO4. The morphology, structure, composition and optical property of the as-prepared nanocomposites were characterized by XRD, SEM, HRTEM, XPS, and UV-vis DRS. Characterization analysis showed that cobalt loaded on the surface of BiVO4 as oxide and the catalyst showed a significant red-shift in the absorption band in the visible region. The photocatalytic activities of the samples were examined by studying the degradation of methylene blue (MB) under visible-light irradiation. The results showed that the photocatalytic activity of Co-BiVO4 was increased by 4 times, compared with pure BiVO4 under visible light irradiation. The best photocatalytic activity was achieved when the molar ratio of Bi: Co was 1:2. The improving mechanisms of bismuth heterojunction and transition metal were further elucidating in the work.