【作者】 万军民；

【导师】 郑旭明；

【作者基本信息】 浙江理工大学 ， 纺织工程， 2011， 博士

【摘要】 随着纺织染料工业的迅速发展,染料的品种和数量日益增加,印染废水已成为水系环境的重点污染源之一。亚甲基蓝作为印染废水中典型的有机污染物之一,是印染污水治理的重要对象。本论文针对这一严重的现实污染问题,选用最具有开发前途的环保型可见光光敏催化材料四苯基卟啉衍生物敏化纳米TiO₂作为降解亚甲基蓝的光催化剂,进行光催化降解的光电子转移动力学及催化氧化性能研究,为处理实际的印染废水提供理论基础及一种高效且经济可行的方法。本文合成并提纯得到了四苯基卟啉、四苯基金属（+2价）卟啉（锌、铜和镍）、四-对羧基苯基卟啉和四-对羧基苯基铜卟啉,以量子波包理论为基础的共振拉曼光谱技术研究卟啉激发态电子转移短时动力学,探明激发态分子最初几十飞秒以内的Franck-Condon区域的光诱导电子转移短时动力学,获得激发态电子转移的途径和通道;利用制备的卟啉化合物敏化TiO₂,制备可见光光敏催化剂,利用这些催化剂催化污水中的亚甲基蓝染料,获得了较多好的效果。（1）测得了四苯基卟啉在二氯甲烷溶液中的电子吸收光谱,结合TD-DFT计算和四轨道模型理论对电子吸收带进行了归属。研究结果表明,四苯基卟啉在二氯甲烷溶液中Franck-Condon区域的短时动力学具有多维性,主要沿着Cm-phenyl,苯环上C=C的对称伸缩振动、C_β=C_β伸缩振动、C_m=C_α对称及不对称伸缩振动,吡咯环呼吸振动,吡咯环变形振动,吡咯二分之一环振动以及吡咯四分之一环振动展开。对于共振拉曼光谱中非全对称模A2的出现,分析认为是由于各电子吸收带之间的振动耦合作用引起的,由此可以推断四苯基卟啉激发态的弛豫过程:基态分子光照受激后激发到激发态B₂,B₂与B₁发生振动耦合使得分子弛豫到B₁,弛豫时间很短,大概在几十飞秒左右,同样B₁带与Q_x带之间发生系间窜跃,B₁激发态向Qx态弛豫时间大约在100飞秒以内,然后又迅速地转变为三线态T的电子。（2）研究金属离子的引入对卟啉激发态的影响,共振拉曼光谱表明,四苯基锌卟啉、四苯基铜卟啉和四苯基镍卟啉Franck-Condon区域的短时动力学主要沿着苯环上C=C的对称伸缩振动、C_β=C_β伸缩振动、吡咯呼吸振动、变形振动和吡咯二分之一环振动展开。但与非金属卟啉相比,锌卟啉的共振拉曼光谱中没有发现非全对称模A₂的出现,是因为金属锌离子的引入不仅使得卟啉的对称性得到了提高,而且导致卟啉B带与Q带之间的能级差增大,激发态弛豫的时间增长到了1.5 ps;但在四苯基铜卟啉和四苯基镍卟啉的共振拉曼光谱中非全对称模A₂的出现,表明在激发态电子的跃迁过程中同样也出现了弛豫过程及单重态向三重态电子的转变过程。（3）测得了四-（对羧基苯基）卟啉和四-（对羧基苯基）铜卟啉在四氢呋喃溶液中激发波长为397.9nm、416nm和438.5nm共振拉曼光谱,并结合TD-DFT计算和四轨道模型理论对电子吸收带进行了归属。获得了共振拉曼光谱来研究金属离子的引入对卟啉激发态的影响,金属铜离子的引入不仅使得卟啉的对称性得到了提高,而且导致卟啉B带与Q带之间的能级差增大。在其共振拉曼光谱中出现了非全对称模A2,表明在激发态电子的跃迁过程中同样也出现了弛豫过程及单重态向三重态电子的转变过程。（4）合成了卟啉和金属卟啉敏化TiO₂光敏催化剂通过傅里叶红外光谱（FT-IR）、扫描电镜（SEM）、原子力显微镜（AFM）、X射线衍射（XRD）和X射线光电子能谱（XPS）进行了表征;并利用其对水溶液中的亚甲基蓝光降解实验,分别对四苯基铜卟啉和四苯基镍卟啉,四-（对羧基苯基）卟啉和四-（对羧基苯基）铜卟啉的催化效果进行比较,发现配位金属对催化效果起重要作用。特别是对于铜离子的引入,导致铜离子参与了催化反应的氧化-还原反应。本论文从量子化学理论及光诱导电子转移动力学方面对卟啉以及金属卟啉敏化TiO₂光敏催化剂进行研究,获得了可见光光敏催化剂在光催化过程中的电子转移动力学机理以及催化降解水中亚甲基蓝的性能和机理,制成一种能够在可见光范围内得到响应的“有机-无机”复合光敏催化剂,通过这些催化剂对水溶液中亚甲基蓝（MB）的光降解效果比较分析,找出影响催化剂催化效果的因素,为开发研究能够真正应用在工业污水处理净化过程中的催化剂进行了有益的探索。更多还原

【Abstract】 As the dye of the rapid developmem of the textile industry, dyes and the increasing number of varieties, printing aIld dyeing wastewater stream environment has become one of the key sources of po1lution. Methylene blue as dyeing wastewater in one of the typical organic pollutants, printing and dyeing is an important target of sewage treatment. This paper against the reality of this serious pollution problem, choose the most promising development of ervironment-friendly materials nano-photocatalytic TiO₂ as a degradation of methylene blue light catalyst, photocatalytic degradation of research, to deal with the actual printing and dyeing waste water to provide an efficient and economically feasible method. Research on relaxation dynamics of excited state of porphyrins contributes greatly to an understanding of the basic mechanism of photosynthesis. With the development and improvement of the theory and technique, scientists can explore the biological photosynthesis further than before, but the short-time dynamics during 0 to 50 fs in Franck-Condon region of the molecular excited state can not be still detected even by the most advanced femto-second ulfast time-resolved laser technique. Resonance Raman spectral techniques, based on Quantum wave packet theory , have a unique advantage on the research of short-time dynamics.In this paper, meso-Tetraphenylporphine、meso-Tetra（p-aminophenyl）porphine、meso-Tetra（p-hydroxyphenyl）porphine、M（II） meso-Tetraphenylporphine（M= Zn、Cu and Ni） have been synthesized and the short-time dynamics of photo-induced Charge-Transfer of them have been investigated by the Resonance Raman spectra in combination with DFT calculation. Main contributions of the present work are summarized as follows.（1） The absorption spectrum of Tetraphenylporphine （TPP） in dichloromethane solution was acquired and explained on the basis of Gouterman’s four orbital model and electronic orbital calculations。Resonance Raman spectra were acquired for TPP in dichloromethane solvent with 397.9 nm、416 nm、435.7 nm and 514 nm excitation wavelengths. The resonance Raman spectra indicate that the short-time photo dynamics of TPP have significant multidimensional character distributed over a wide variety of vibrational modes such Cm-ph stretch,phenyl C=C stretch、the Porphin ring C_β=C_βstretch、the Porphin ring Cm=Cαstretch, Porphin ring breath, pyrrole deformation modes, pyrrole half-ring stretching modes and pyrrole quarter-ring stretching modes, while the vibrational modes in wavenumber and in description for different resonance Raman spectra are very similar, the intensity patterns are very different, it can be explained that the major short-time photo dynamics in the Franck-Condon region of the B band occurs mostly along the nominal Cm-ph stretch and the nominal Porphin ring C_β=C_βstretch, while for the photo dynamics of the Qx band occurs mainly along the nominal Porphin ring Cβ=Cβand the nominal Cm-ph stretch. The appearance of A2 non-total symmetry vibrational modeν71 [ν（CmCα）as stretch]andν73、ν74 [pyrrole quarter-ring stretching modes] indicate that while most of the excited state structural dynamics are along the total symmetry vibrational reaction coordinates, it also moves along the non-total symmetry reaction coordinate significantly, which means the existence of the Franck-Condon region vibronic coupling between the By、Bx and Qy electronic states. Reference to experimental results and literature, we have deduced the relaxation dynamics of porphyrin. In our model of relaxation process, the two higher singlet states undergo internal conversion to Qx within 100 fs.（2） We have also conducted the study of Zn（II） meso-Tetraphenylporphine, Cu（II） meso-tetraphenyl porphyrin（CuTPP） and Ni（II） meso-tetraphenyl porphyrin（NiTPP） . Compared with meso-Tetraphenylporphine, we found that although the main vibration modes in the resonance Raman spectra did not changed, the reaction coordinates or displacements also occured with Cm-ph stretch、phenyl C=C stretch、the Porphin ring Cβ=Cβstretch、the Porphin ring Cm=Cαstretch、Porphin ring breath、pyrrole deformation modes and pyrrole half-ring stretching modes. With the introduction of metal ion, the metal porphyrin not only have a higher symmetry, which cause the vanish of A2 non-total symmetry vibrational modes, but also make the energy gap larger, which result in 1.5 ps of relaxation time.（3） The Resonance Raman spectrum of Cu meso-tetra（4-carboxyphenyl）porphyrin（CuTCPP） and meso-tetra（4-carboxyphenyl） porphyrin（TCPP） in tetrahydrofuran solution was acquired and explained on the basis of Gouterman’s four orbital model and electronic orbital calculations.The resonance Raman spectra indicate that the short-time photo dynamics of CuTCPP and TCPP also have significant multidimensional character with the reaction coordinates or displacements occurring with Cm-ph stretch、phenyl C=C stretch)、the Porphin ring Cβ=Cβstretch、the Porphin ring Cm=Cαstretch、Porphin ring breath、pyrrole deformation modes、pyrrole half-ring stretching modes and pyrrole quarter-ring stretching modes.With the introduction of metal ion, the metal porphyrin not only have a higher symmetry, which cause the vanish of A2 non-total symmetry vibrational modes, but also make the energy gap larger.（4） Porphyrin-TiO₂ was synthesized and characterized by FT-IR、SEM、AFM、XRD and XPS spectroscopy. The photocatalytic activity of TiO₂ samples which are impregnated with porphyrins and metalloporphyrins as sensitizers have been investigated by carrying out the photo-degradation of methylene blue as a proaction in aqueous suspension and under visible light. Find the coordination of metal on catalytic is the key factor.In this paper, meso-Tetraphenylporphine、meso-Tetra（p-aminophenyl）porphine、meso-Tetra（p-hydroxyphenyl）porphine、M（II） meso-Tetraphenylporphine（Zn、Cu and Ni） have been synthesized and the short-time dynamics of photo-induced Charge-Transfer of them have been investigated by the Resonance Raman spectra in combination with DFT calculation. The Porphyrin-TiO₂ catalyst shows high photocatalytic degradation activity of MB in aqueous solution under visible light irradiation. The H2TCPP and/or CuTCPP are chemisorbed on the surface of TiO₂ through the O=C-O-Ti chemical bond, The formed O=C-O-Ti bond between H2TCPP or CuTCPP and TiO₂ can act as the electron transfer channel, accelerating the photoexcited sensitizer electron injection to conduction band of TiO₂. The introduction of metal ion makes the metallic porphyrin has a higher molecular symmetry and make the energy gap between B and Q electronic states larger, which further increases the photocatalysis efficiency of TiO₂. The visible light photocatalysis mechanism of the dye-sensitized TiO₂ was further discussed. The experimental results confirmed that it was significantly beneficial to the photodegradation of MB solution in the presence of Porphyrin-TiO₂ under visible light, which could provide a potential approach for an energy saving application in wastewater treatment.更多还原