【作者】 赵晗；

【导师】 邹海峰；

【作者基本信息】 吉林大学 ， 化学（应用化学）， 2025， 硕士

【摘要】 随着全球工业化进程加快,化石能源的过度开采与消耗不仅导致能源危机,更在开采、运输及燃烧过程中释放大量有机污染物（如石化废水中的罗丹明B（Rhodamine B,Rh B）、甲基橙（Methyl Orange,MO）染料及抗生素四环素（Tetracycline,TC））,对生态环境和人类健康构成严重威胁。光催化作为一种环保型绿色技术,在常温常压下能直接利用太阳能生成活性自由基,可将有机染料（如Rh B、MO）等)及抗生素（如TC）等有害污染物高效降解为无害物质,从而有效净化环境。在各种半导体光催化剂中,二氧化钛（TiO₂）因具有良好的物理化学稳定性等诸多优点而受到广泛关注。然而,TiO₂光生载流子复合快、易团聚,导致光催化效率较低。因此,提升TiO₂中光生载流子的分离效率,以优化光催化活性,是目前亟待攻克的科学难题。本论文采用水热法制备了不同形貌的TiO₂光催化剂,通过引入有机助催化剂对TiO₂进行修饰改性。系统研究了制备样品的晶型结构、微观形貌、元素化学状态、孔隙特征及光电化学特性。阐明了光催化活性增强的内在机制与污染物降解机理,探究了催化剂的循环稳定性及环境适应性。取得以下主要研究成果:1.通过溶剂热合成方法,成功合成了具有绣球花形貌的纯锐钛矿相TiO₂光催化剂（FT）,探讨了特殊形貌的形成机理。通过水热法引入乙酸（Acetic acid,AA）作为有机助催化剂对TiO₂进行表面改性。探究复合材料（AFT）的光催化活性。结果表明,AFT复合材料的光催化活性分别是纯TiO₂和Degussa P25（一种商用TiO₂光催化剂,P25）的2.97和4.47倍,可归因于AFT绣球花型形貌具有较大比表面积,可提供大量的反应活性位点,增加了与目标降解污染物的接触面积。AA通过双齿螯合的方式与TiO₂偶联,增强了复合材料的稳定性。二者之间通过形成电荷转移复合物（Charge Transfer Complexes,CTCs）,导致复合材料导带（Conduction band,CB）位置负移。在光照下驱动配体HOMO轨道的电子向TiO₂的CB转移,CB电子密度增大,生成更多的超氧阴离子自由基（·O₂^-）,在光催化降解有机污染物中发挥作用,从而提升了光催化降解Rh B的效率。2.通过水热合成技术,制备了不同巴豆酸（Crotonic Acid,CA）含量的TiO₂/CA复合材料,探究了有机助催化剂对TiO₂光催化性能的影响。光催化结果表明,TiO₂/CA复合材料在16 min内对TC的去除率为99.5%,光催化速率是纯TiO₂的2.43倍。同时TiO₂/CA复合材料在30 min内对有机染料如Rh B、MO、亚甲基蓝（Methylene Blue,MB）、孔雀石兰绿（Malachite Green,MG）均有93%以上的降解率。机理研究表明,·O₂^-和空穴（h⁺）都参与了光催化反应。同时,含共轭π结构的有机助催化剂是输送空穴的优异材料,有效提升了光生载流子的分离与迁移效率,大幅增强了光催化活性。更多还原

【Abstract】 With the acceleration of global industrialization,over-exploitation and consumption of fossil energy not only lead to the energy crisis,but also release a large number of organic pollutants（e.g.,Rhodamine B（Rh B）,Methyl Orange（MO）dyes,and the antibiotic tetracycline（TC））in petrochemical wastewater in the process of extraction,transportation,and combustion,posing a serious threat to the ecological environment and human health.),posing a serious threat to the ecological environment and human health.As an environmentally friendly green technology,photocatalysis can directly utilize solar energy to generate active radicals at room temperature and pressure,which can efficiently degrade harmful pollutants such as organic dyes（e.g.,Rh B,MO,etc.）and antibiotics（e.g.,TC）into harmless substances,thus effectively purifying the environment.Among various semiconductor photocatalysts,titanium dioxide（TiO₂）has received widespread attention due to many advantages such as good physicochemical stability.However,TiO₂ photogenerated carriers compound quickly and are prone to agglomeration,resulting in a low photocatalytic efficiency.Therefore,enhancing the separation efficiency of photogenerated carriers in TiO₂ to optimize the photocatalytic activity is an urgent scientific challenge.In this thesis,TiO₂ photocatalysts with different morphologies were prepared using the hydrothermal method,and TiO₂ was modified by introducing organic co-catalysts.The crystalline structure,microscopic morphology,elemental chemical state,pore characteristics,and photoelectrochemical properties of the prepared samples were systematically investigated.The intrinsic mechanisms of enhanced photocatalytic activity and pollutant degradation were elucidated,and the cyclic stability and environmental adaptability of the catalysts were investigated.The following main research results were achieved:1.Pure anatase TiO₂ photocatalysts（FT）with hydrangea morphology were successfully synthesized by solvothermal synthesis,and the formation mechanism of the special morphology was investigated.The surface modification of TiO₂ was carried out by introducing acetic acid（AA）as an organic co-catalyst via hydrothermal method.The photocatalytic activity of the composites（AFT）was explored.The results showed that the photocatalytic activities of the AFT composites were 2.97 and 4.47 times higher than those of pure TiO₂ and P25,respectively,which can be attributed to the large specific surface area of the AFT hydrangea-type morphology,which provides a large number of reactive sites and increases the contact area with the target pollutants for degradation.The AA was coupled with the TiO₂ by means of double-dentate chelating,which enhanced the stability of the composites.Between the two,it leads to a negative shift in the position of the composite’s conduction band（CB）through the formation of Charge Transfer Complexes（CTCs）.The electron transfer from the HOMO orbitals of the ligand to the CB of TiO₂ was driven by light,and the electron density of the CB was increased to generate more superoxide anion radicals（·O₂^-）,which played a role in the photocatalytic degradation of organic pollutants,thus enhancing the efficiency of photocatalytic degradation of Rhodamine B（Rh B）.2.TiO₂/CA composites with different crotonic acid（CA）contents were prepared by hydrothermal synthesis to investigate the effect of organic co-catalysts on the photocatalytic performance of TiO₂.The photocatalytic results showed that the TiO₂/CA composites removed 99.5%of tetracycline（TC）within 16 min,and the photocatalytic rate was 2.43 times higher than that of pure TiO₂.Meanwhile,the TiO₂/CA composites degraded organic dyes such as Rh B,Methyl Orange（MO）,Methylene Blue（MB）,and Malachite Green（MG）by more than 93%in 30 min.Mechanistic studies showed that both·O₂^-and hole（h⁺）were involved in the photocatalytic reaction.Meanwhile,the conjugatedπ-structure of the organic co-catalyst containing the organic co-catalyst is an excellent material for transporting holes,which effectively improves the separation and migration efficiency of the photogenerated carriers,and dramatically enhances the photocatalytic activity.更多还原