【作者】 李昊；

【导师】 李伟； 任翔宇；

【作者基本信息】 浙江大学 ， 材料与化工（专业学位）， 2025， 硕士

【摘要】 含氯挥发性有机物(CVOCs)的高效安全治理亟需开发兼具低温催化活性、抗氯中毒性及低副产物生成特性的催化材料。本研究以氯苯为模型污染物,围绕铈钛基催化剂在CVOCs催化降解中的构效关系和反应机理开展系统研究。首先,通过构建铈钛协同催化体系揭示了金属间相互作用对反应路径的调控机制;其次,提出过渡金属掺杂策略实现深度氧化与脱氯能力的协同提升;最后,阐明复杂工况下多组分VOCs的反应机制并开发抗积碳改性催化剂。论文主要结论如下:(1)阐明了铈钛金属协同作用对催化性能及抗氯机制的影响。Ce0.3Ti0.7催化剂具有最佳的催化活性和稳定性,其T90为280℃并可长期稳定运行。结合表征结果分析,Ce0.3Ti0.7的最佳催化性能归因于较高的氧空位浓度、较强的表面还原性和酸性。增加的电子转移能力形成了更多的Ce3+和Ti3+,进而诱导氧空位的生成,显著提升表面氧物种的流动性,有效增强催化剂的催化活性;同时CeTi金属间的相互作用提升了催化剂的酸性,促进了 C-Cl的断裂和Cl的脱附,实现了氯苯的稳定脱除。(2)提出金属掺杂策略构筑深度氧化能力和脱氯能力协同提升的Cr改性铈钛基催化剂,揭示了酸性和氧化还原性的协同作用机制。在改性的铈钛基催化剂中,(CeTi)2Cr1催化剂的T90降至220℃,矿化率由63%提升至95%,且能在255℃实现氯苯的稳定脱除。结合表征结果分析,Cr掺杂诱导晶格畸变产生氧空位,提升了晶格氧的移动性,增加了表面吸附氧含量,从而显著增强催化剂的低温氧化能力。与此同时,Cr的引入提升了催化剂的酸性位点密度,促进了 Cl的脱除。in situ DRIFTS和GC-MS结果证实,Cr改性提升了催化剂的深度氧化能力,有效促进苯环中C=C的裂解,且通过强化Cl脱附有效抑制氯化反应,进而减少多氯副产物的生成。(3)揭示氯苯、甲苯协同去除过程中的相互作用机制并开发抗积碳催化剂。(CeTi)2Cr1催化剂在高空速高浓度的条件下仍保持稳定优异的催化活性,且对其他典型的单一 CVOCs及甲苯、氯苯混合体系均展示出良好的广谱催化性能。结合O2-TPO和in situ DRIFTS结果,发现当甲苯与氯苯共存时,甲苯氧化过程中生成的积碳中间体会显著抑制氯苯的进一步氧化。针对这一关键问题,通过引入Pt颗粒构建改性铈钛基催化剂,借助Pt优异的深度氧化能力促进积碳中间物种的快速脱除,最终实现多组分VOCs在255℃的稳定降解。更多还原

【Abstract】 Efficient and safe treatment of chlorinated volatile organic compounds(CVOCs)requires the development of catalytic materials with low-temperature activity,resistance to chlorine poisoning,and low byproduct generation.This study takes chlorobenzene as the model pollutant and systematically investigates the structureactivity relationships and reaction mechanism of cerium-titanium(CeTi)based catalysts in CVOCs catalytic degradation.First,the regulatory mechanism of intermetallic interaction on reaction pathways is revealed by constructing a CeTi synergistic catalytic system.Second,the strategy of transition metal doping is proposed to synergistically enhance deep oxidation and dechlorination capabilities.Finally,the interaction mechanism of multi-component VOCs under complex industrial conditions are elucidated,and novel anti-coking modified catalysts are developed.The main conclusions are as follows:(1)The influence of CeTi synergy on the catalytic performance and chlorine resistance mechanism of chlorobenzene is clarified.The Ce0.3Ti0.7 catalyst exhibits optimal activity and stability,achieving a T90 of 280 ℃ and long-term stable operation.Characterization results demonstrate that its superior performance stems from high oxygen vacancy concentration,enhanced surface reducibility,and strong acidity.Improved electron transfer capacity generates more Ce3+and Ti3+species,inducing oxygen vacancy formation,which significantly enhances oxygen species mobility and catalytic activity.Concurrently,CeTi interaction strengthens surface acidity,promoting C-Cl bond cleavage and chlorine desorption,thereby achieving stable chlorobenzene removal.(2)Metal doping strategy is proposed to construct a Cr-modified CeTi based catalyst with synergistic enhancement of deep oxidation capacity and dechlorination capacity,revealing the synergistic mechanism of acidity and redox properties.Crmodified CeTi based catalysts(CeTi)2Cr1 achieves a reduced T90 of 220℃,increased mineralization efficiency from 63%to 95%,and stable chlorobenzene degradation at 255℃.Cr doping induces lattice distortion,generating oxygen vacancies and enhancing lattice oxygen mobility,thereby improving low-temperature oxidation capacity.Additionally,Cr incorporation increases acidic site density,facilitating chlorine removal.in situ DRIFTS and GC-MS results confirm that Cr modification enhances the catalyst’s deep oxidation capacity,effectively promoting the cleavage of C=C bonds in benzene rings.By enhancing Cl desorption and deep oxidation capacity,it suppresses chlorination reaction,thereby reducing the formation of polychlorinated byproducts.(3)The competitive reaction mechanism of multi-component VOCs under complex industrial conditions is systematically revealed,and novel anti-coking catalysts are successfully developed.The(CeTi)2Cr1 catalyst maintains stable activity under high space velocity and concentration conditions and demonstrates broadspectrum catalytic performance for single CVOCs and chlorobenzene-toluene mixtures.O2-TPO and in situ DRIFTS results reveal that carbonaceous intermediates from toluene oxidation inhibit chlorobenzene degradation.To address this,Pt nanoparticles are introduced into CeTi based catalysts,leveraging its superior deep oxidation capacity to rapidly remove carbonaceous intermediates,achieving stable multi-component VOCs degradation at 255℃.更多还原