氢氟酸加入量对钛基半导体结构演变及光催化性能的影响

发布时间：2018-06-23 21:17

本文选题：氢氟酸 + 钛基半导体　；参考：《物理化学学报》2017年10期

【摘要】：以钛酸丁酯为钛源,氢氟酸为氟源,采用溶剂热法制备了一系列钛基半导体纳米晶,考察了氢氟酸加入量对纳米晶结构演变的影响,并通过光催化产氢、光降解罗丹明B及瞬态光电流响应测试了所得纳米晶的光催化性能。当不加氢氟酸时,所得纳米晶为TiO_2纳米颗粒,主要暴露{101}面。加入少量氢氟酸时,所得纳米晶为主要暴露{001}面的TiO_2纳米片,这是由于氟离子吸附于纳米晶表面,降低{001}面表面能所致。由于{001}面与{101}面间的晶面异质结促进了载流子分离,该样品表现出了最高的光催化性能。继续增加氢氟酸加入量,氟离子开始进入晶格构成新晶相,所得纳米晶的表面与体相均形成TiO_2与TiOF_2混合相,形貌呈现片层堆叠结构,光催化性能下降。当进一步增加氢氟酸加入量后,氟离子全部进入晶格形成大颗粒(NH_4)_(0.3)TiO_(1.1)F_(2.1)。因其具有不适宜光催化反应的能带结构,该物质表现出了较差的光催化活性,但其可作为制备氮、氟掺杂钛基半导体材料的前驱体使用。
[Abstract]:A series of titanium based semiconductor nanocrystals were prepared by solvothermal method using butyl titanate as titanium source and hydrofluoric acid as fluorine source. The effect of the amount of hydrofluoric acid on the evolution of nanocrystalline structure was investigated. Photodegradation of Rhodamine B and transient photocurrent response were used to determine the photocatalytic properties of the nanocrystals. When hydrofluoric acid is not added, the resulting nanocrystals are TiO-2 nanoparticles, mainly exposed to {101} plane. When a small amount of hydrofluoric acid was added, the obtained nanocrystals were TiO2 nanoparticles which mainly exposed {001} surface, which was caused by fluoride ion adsorbing on the surface of nanocrystalline and reducing the surface energy of {001} surface. Because the heterojunction between {001} plane and {101} plane promotes carrier separation, the sample exhibits the highest photocatalytic performance. With increasing the amount of hydrofluoric acid, fluorine ions began to enter the lattice to form a new crystal phase. Both the surface and bulk phases of the nanocrystals were mixed with TiOStack _ 2 and TiOF _ 2. The morphology of the nanocrystals presented lamellar stacking structure and the photocatalytic performance decreased. When the amount of hydrofluoric acid was further increased, fluorine ions all entered the lattice to form large particles (NH _ 4) _ (0.3) TIO _ (1.1) F _ (2.1). Because of its unsuitable band structure for photocatalytic reaction, the compound exhibits poor photocatalytic activity, but it can be used as a precursor for the preparation of nitrogen and fluorine-doped titanium based semiconductor materials.
【作者单位】：天津大学化工学院天津化学化工协同创新中心天津市应用催化科学与工程重点实验室;
【基金】：国家自然科学基金(21476159) 天津市自然科学基金(15JCZDJC37400,15JCYBJC23000)资助项目~~
【分类号】：O643.36;O644.1

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