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摘要本论文利用一步水热法和连续水热法两种方法分别合成了可磁分离的BiVO4-CoFe2O4-石墨烯和BiVO4-Fe3O4-石墨烯半导体复合光催化剂。通过X射线衍射谱(XRD)，紫外-可见光光谱(UV-Vis spectroscopy)，拉曼光谱(Raman)，X射线光电子能谱(XPS)，透射电子显微镜(TEM)等手段对催化剂的成分和形貌进行了表征。在暗室中测试了光催化剂对不同类型染料的吸附性能，并在模拟太阳光下进行了相应染料的光催化降解试验，验证了光催化剂对染料的吸附作用与降解作用存在正相关的关系。通过对两类光催化剂进行的光电流暂态和电化学交流阻抗谱的测试，结合TEM和XRD图，推测出两类光催化剂光催化效果提高的原因在于石墨烯表面的片状BiVO4对染料的吸附性能更好，而且片状的形貌更有利于BiVO4暴露高能晶面，提升光催化降解效果。
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结果显示，两类可磁分离的BiVO4-石墨烯半导体复合光催化剂分散于水相后，都可以通过外加磁场简单地将催化剂分离。与BiVO4-石墨烯半导体复合光催化剂相比，可磁分离的BiVO4-CoFe2O4-石墨烯和BiVO4-Fe3O4-石墨烯半导体复合光催化剂在可见光下催化降解水中的亚甲基蓝(MB)，罗丹明B(RhB)等染料的性能不仅没有降低，而且还具有较好的磁分离性质，解决了催化剂难分离的难题。10389
关键词 钒酸铋 石墨烯 光催化剂 磁分离 可见光辐射
毕业设计说明书（论文）外文摘要
Title Preparation and Photocatalytic Performance Study of Graphene-based Magnetic Visible-light Driven Catalyst
Abstract
The magnetically separable BiVO4-CoFe2O4-graphene and BiVO4-Fe3O4-graphene semiconductor photocatalysts were prepared by a one-step hydrothermal method and a continuous hydrothermal method, respectively. The as-prepared catalysts were characterized by X-ray diffraction (XRD), UV-vis spectra, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) techniques. The absorption activity of the photocatalysts was determined in dark and the photocatalytic activity was determined under visible light irradiation. The results show that BiVO4-CoFe2O4-graphene and BiVO4-Fe3O4-graphene semiconductor photocatalysts reveal high photocatalytic activity for degradation of methylene blue (MB),Rhodamine B (RhB) in water under visible-light irradiation. After conducting the Electrochemical impedance spectroscopy (EIS) and photocurrent test, combining the TEM images and XRD spectroscopy, we can conclude that the enhanced photocatalytic activity can be attributed to the nanoplate-like BiVO4 on graphene sheets. Because the BiVO4 nanopaltes can offer more active adsorption sites and photocatalytic reaction centers. Moreover, the nanoplate can lead to highly expose of active facets, which could offer an enhanced photocatalytic activity. CoFe2O4 and Fe3O4 nanoparticles themselves have excellent magnetic properties, which make the BiVO4-CoFe2O4-graphene and BiVO4-Fe3O4-graphene semiconductor photocatalysts magnetically recyclable in a suspension system.
Keywords BiVO4 Graphene Photocatalyst Magnetic separation Visible-light irradiation
目 次
1 绪论 1
1．1 光催化和光催化剂 1
1.1.1 光催化 1
1.1.2 光催化剂 1
1．2 半导体光催化剂 1
1.2.1 半导体光催化剂 1
1.2.2 半导体光催化剂的催化机理 2
1．3 石墨烯掺杂的半导体光催化剂 2
1.3.1 石墨烯及其制备 2
1.3.2 半导体光催化剂的掺杂 4
1.3.3 石墨烯掺杂的半导体光催化剂 4