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以Na2WO4.2H2O为主要原料,采用液相法(80℃)和离子交换-水热法(150℃)分别制备了六方WO3.0.33H2O和以正交相为主的混合晶型WO3.0.33H2O。通过对2种晶型WO3.0.33H2O材料进行X射线衍射(XRD)、场发射电子扫描显微镜(FE-SEM)、红外光谱(FTIR)、X射线光电子能谱(XPS)和循环伏安测试,表征了产物的晶相和结构等。正交WO.30.33H2O结构中由于相邻钨氧八面体层的相互位移而形成空隙,六方WO3.0.33H2O结构中没有位移则形成孔道;正交WO3.0.33H2O具有比六方WO3.0.33H2O更短键长的W=O和更负的导带位置。紫外-可见透射光谱研究表明,六方WO.30.33H2O具有更明显的电致变色效应,可能是因为结构中的孔道使H+易扩散使六方WO.30.33H2O更易发生氧化还原反应。光催化性能研究表明,正交WO3.0.33H2O具有更负的导带位置,价带电子跃迁后易于向电子受体转移,抑制了电子和空穴的复合,使得混合晶型WO3.0.33H2O的紫外光光催化能力相对六方WO.30.33H2O更强。
Using Na2WO4.2H2O as the main raw material, a hexagonal WO3.0.33H2O and a mixed phase of mainly orthorhombic phase WO3.0.33H2O were prepared by liquid-phase method (80 ℃) and ion exchange-hydrothermal method (150 ℃) . Through the X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), infrared spectroscopy (FTIR), XPS and cyclic voltammetry of two kinds of samples of WO3.0.33H2O, Characterization of the product of the crystal phase and structure. Orthogonal WO.30.33H2O structure due to the mutual displacement of adjacent tungsten oxide octahedra to form voids, hexagonal WO3.0.33H2O structure without displacement of the formation of pores; orthogonal WO3.0.33H2O has more than the hexagonal WO3.0.33H2O more Short key long W = O and more negative conduction band position. The results of UV-Vis transmission spectroscopy showed that the hexagonal WO30.33H2O has a more obvious electrochromic effect, probably because the pore of the structure makes H + diffusible, making the hexagonal WO.30.33H2O more susceptible to redox reactions. Photocatalytic performance studies show that the orthogonal WO3.0.33H2O has a more negative conduction band position, valence band electronic transition easily after the transfer to the electron acceptor, inhibition of electron and hole recombination, making the mixed crystal form WO3.0.33H2O UV photocatalytic capacity of the hexagonal WO.30.33H2O stronger.