【作者】 李莉；

【导师】 郭伊荇；

【作者基本信息】 东北师范大学 ， 物理化学， 2009， 博士

【摘要】 本论文致力于高效复合光催化材料的设计制备、表征与催化性能研究,针对所合成复合光催化材料的特点,系统研究了不同合成方法对复合材料晶型结构与表面形貌的影响,考察了该系列复合材料在不同光源辐射下的光催化性能。利用溶胶-凝胶再结合程序升温溶剂热方法,制备了具有可见光光催化活性的H₃PW₁₂O₄₀掺杂TiO₂锐钛矿纳米双孔光催化材料-H₃PW₁₂O₄₀/TiO₂。通过电感耦合等离子原子发射光谱（ICP-AES）、固体核磁共振波谱(³¹P MAS NMR)、X-射线粉末衍射（XRD）、紫外–可见漫反射光谱（UV/DRS）、红外光谱（FT-IR）和拉曼散射光谱等表征手段对合成材料进行了组成和结构表征。结果表明,复合材料中杂多酸H₃PW₁₂O₄₀的基本结构仍然保留,而且与二氧化钛之间通过化学作用相结合,并具有锐钛矿晶型结构。利用透射电镜（TEM）以及N₂吸附测定等表征手段对复合材料的形貌以及表面物理化学性质进行了表征。结果表明,H₃PW₁₂O₄₀/TiO₂具有微孔（0.6 nm）和介孔（3.0 nm）双重孔径,且BET比表面积有了较大提高。通过对有机杀虫剂-甲基对硫磷的可见光光催化实验,研究了H₃PW₁₂O₄₀/TiO₂在非均相体系中的光催化活性。结果表明,H₃PW₁₂O₄₀/TiO₂在可见光照射下具有较高的光催化活性,可有效降解上述有机污染物。H₃PW₁₂O₄₀/TiO₂较高的光催化活性源于该复合材料的光吸收特性、表面物理化学性质以及多酸和TiO₂之间的协同作用。另外,以有机染料孔雀石绿（MG）为模型分子,考察了微波无极灯的形状、微波功率、溶液初始浓度和催化剂用量对微波光催化降解效果的影响。在最佳微波反应条件下,考察了复合光催化材料H₃PW₁₂O₄₀/TiO₂对刚果红、酸性黑和酸性品红的光催化降解情况,并且分别进行了H₃PW₁₂O₄₀/TiO₂微波增强光催化降解MG以及在高压汞灯照射下的H₃PW₁₂O₄₀/TiO₂光催化降解MG的对比实验。结果表明,在微波场作用下,H₃PW₁₂O₄₀/TiO₂的光催化活性被显著增强。采用非离子表面活性剂C₁₈H₃7（OCH₂CH₂）10OH（Brij-76）作为模板剂,通过溶胶-凝胶-程序升温溶剂热一步合成法制备了H₆P₂W₁₈O₆₂/TiO₂（Brij-76）复合光催化剂。分别采用电感耦合等离子原子发射光谱（ICP-AES）、X-射线粉末衍射（XRD）、扫描电镜（SEM-EDX）、透射电镜（TEM）、N₂吸附-脱附和红外光谱（FT-IR）等检测手段对合成材料的组成、结构与表面物理化学性质进行了表征。结果表明,使用非离子表面活性剂Brij-76制备的H₆P₂W₁₈O₆₂/TiO₂（Brij-76）复合光催化剂具有介孔结构（3.3 nm）和较大的比表面积（99.78 m2/g）,且复合材料中多酸H₆P₂W₁₈O₆₂的基本结构未发生明显变化。与TiO₂相比,其孔径有序性大幅度提高,粒子的聚集度降低,表面酸性显著增加。在光催化性能研究中,选择一氯苯为探针分子,考察了复合光催化材料H₆P₂W₁₈O₆₂/TiO₂（Brij-76）在微波作用下的光催化活性,并与传统紫外和可见光光催化方式进行了对比。实验结果显示,H₆P₂W₁₈O₆₂/TiO₂（Brij-76）在可见光、紫外光以及微波增强光催化降解一氯苯的实验中表现出比锐钛矿型TiO₂和母体H₆P₂W₁₈O₆₂更高的催化活性。采用灼烧、溶胶-凝胶再结合程序升温溶剂热、模板等不同合成方法制备了复合金属氧化物光催化材料TiO₂-ZrO₂,并采用XRD、SEM-EDX、TEM、N₂吸附-脱附和TPD等表征手段对不同合成方法所制备的复合金属氧化物光催化材料的结构与表面物理化学性质进行了表征。合成过程中,研究了纳米复合材料TiO₂-ZrO₂中ZrO₂的掺杂量不同对复合材料的结构与催化性能的影响,并在合适的掺杂量下,分别采用程序升温溶剂热法和模板法合成了TiO₂-ZrO₂ （TPHT）,TiO₂-ZrO₂ (P₁₂₃-TPHT)两种催化剂,探讨了不同合成方法对其催化活性的影响。通过紫外区和可见区的光催化降解染料亚甲基蓝、罗丹明B和水杨酸的实验,考察了不同合成方法制备的TiO₂-ZrO₂复合光催化材料的光催化活性。实验结果表明,所合成的复合材料TiO₂-ZrO₂的催化活性均高于单体TiO₂和ZrO₂。其中,采用非离子表面活性剂EO₂₀PO₇₀EO₂₀(EO=CH₂CH₂O;PO=CH₂（CH₃）CHO;P₁₂₃)为结构导向剂,通过溶胶-凝胶和程序升温溶剂热方法制备的复合金属氧化物TiO₂-ZrO₂(P₁₂₃-TPHT)比表面积最大,催化活性最高。更多还原

【Abstract】 A series high performance photocatalytic composits were prepared and well-characterized, and their catalytic activities were studied. Based on the characteristic of prepared nanocomposits, it was systemically discussed that the crystalline phase and surface morphology of the composites were affected by different synthesized methods. Moreover, the photocatalytic activities of as-prepared composites were studies under different light irradiation.New and efficient heterogeneous photocatalytic material, H₃PW₁₂O₄₀/TiO₂ with anatase crystalline phase, dual-pore structures （micro- and meso-porosity）, and nanometer sizes （average particle size of 6 nm） was prepared by combination of the methods of sol-gel and hydrothermal treatment at a lower temperature （200°C, 2°C/min）. Composition, structure, physicochemical properties, and surface morphology of the composite were characterized by inductively coupled plasma atomic emission spectrum （ICP-AES）, X-ray diffraction （XRD） patterns, UV diffuse reflectance spectroscopy （UV/DRS）, ³¹P magic-angle spinning （MAS） NMR, Raman scattering spectra, nitrogen adsorption/desorption determination, and transmission electron microscopy （TEM）, respectively. It indicated that the primary Keggin structure remained intact after immobilization of the unit into the TiO₂ network, and hydrogen bonding and chemical interactions between the unit and the anatase network existed in the composite. The composite exhibited visible-light photocatalytic activity to degradation of an aqueous organophosphorus pesticide, parathion-methyl. The high photoactivity of as-prepared nanocomposite could be attributed the higher surface, dual-pore structures, and the synergistic effect existed between the H₃PW₁₂O₄₀ and the TiO₂ matrix. In addition, photodegradation of malachite green （MG） as the model molecular by microwave discharge electrodeless lamps （MDELs） was studied. The effects of different parameters in degradation of MG were discussed, including the MDEL shape, the microwave power, the initial solution concentration and the catalyst dosage. MG was degraded completely within 30 min by U-MDEL when microwave power was 600 W. Additionally, the photodegradation of congo red, acid black, acid fuchsine and salicylic acid had been investigated under the optimum reaction condition of the microwave-enhanced photocatalysis by the use of the composite H₃PW₁₂O₄₀/TiO₂. Compared with the results of the experiment with only MDEL, the time that complete degradation of four organic contaminants needed significantly reduced. The microwave-enhanced photocatalytic degradation took on a good effect, therefore, the use of microwave-enhanced photocatalysis was promising in treating organic contaminants. The H₆P₂W₁₈O₆₂/TiO₂ （Brij-76） composite was prepared by the combination of nonionic surfactant C₁₈H₃7（OCH₂CH₂）10OH （Brij-76） as the template and a single-step sol-gel-hydrothermal method. As-synthesized composite was characterized by FT-IR, XRD, SEM, EDX, N₂ absorption-desorption and NH₃-TPD. The results showed that the average pore diameter of the composite H₆P₂W₁₈O₆₂/TiO₂ （Brij-76） was ca. 3.3 nm, and that of large surface area was 99.78 m²/g. Additionally, the aggregation of particles was effectively inhibited, and surface acidity increased substantially. The photocatalytic eliminations of monochlorobenzene were used as model reaction to evaluate the mirowave enhanced photocatalytic activity of the composite, which was compared with conventional photocatalytic mode with UV-light and visible light. The results showed that the composite H₆P₂W₁₈O₆₂/TiO₂ （Brij-76） can more effectively degradate monochlorobenzene than anatase TiO₂ and H₆P₂W₁₈O₆₂, and which took on a high catalytic activity under mirowave irradiation.The TiO₂-ZrO₂ mixed oxides were prepared by different synthesis methods about calcined or combination of the methods of sol-gel and hydrothermal treatment and template method. Structures, physicochemical properties, and surface morphology of the as-composites were characterized by XRD, nitrogen absorption-desorption, SEM-EDX and TPD techniques. Moreover, the effects of TiO₂-ZrO₂ with different proportion on the structure and their catalytic activities were researched. The results indicated that as-composites were active to decompose aqueous dyes methylene blue, rhodamine B and salicylic acid, and their photocatalytic activities were higher than TiO₂ and ZrO₂. Thereinto, TiO₂-ZrO₂(P₁₂₃-TPHT) mixed oxides was prepared by a one-step sol-gel-solvothermal method in the presence of a triblock copolymer surfactant,Poly（ethylene glycol）-block-poly（propylene glycol）-block-poly（ethyleneglycol）,P₁₂₃(EO₂₀PO₇₀EO₂₀;EO=CH₂CH₂O; PO=CH₂（CH₃）CHO) as the template, of which the surface area and photocatalytic activity was the best.更多还原