催化法治理挥发性有机物污染的研究进展

Recent progress on VOC pollution control via the catalytic method

挥发性有机物(VOCs)具有毒性、刺激性、致癌性和致畸作用,主要来源于石油化工、制药、制鞋业、电子制造和餐饮油烟等人类活动.VOCs和NO_(x)是生成细颗粒物(PM2.5)和臭氧(O3)等二次污染物的重要前体物,严重制约了社会的可持续发展,并对人类健康构成了严重威胁.因此,治理VOCs污染对于降低环境风险至关重要.鉴于实际工况条件复杂,多种VOCs(烷烃、芳香烃、卤代烃、醛酮和醇酯等)共存,它们的极性和浓度存在差异,在催化剂上的吸附、活化和转化过程不同,因此,对催化剂高效消除多组分VOCs的能力提出了挑战.目前,在众多净化VOCs的技术中,催化氧化法因其高效率、低能耗等优势在末端污染控制中越来越受到重视.本文主要介绍了近十年来通过热催化或光热催化消除污染物的代表性研究工作.首先,系统地总结了用于热催化消除单一VOC和典型多组分VOCs(例如,医药行业:甲苯和丙酮;家具涂料行业:甲苯和异己烷等)、协同消除VOCs和NO_(x),以及VOCs资源化利用(选择催化转化VOCs为高附加值产品)而设计和制备的各种具有独特形貌和结构的过渡金属氧化物纳米催化剂、贵金属颗粒纳米催化剂、贵金属单原子催化剂等,并探讨了其氧化还原性、酸性、氧物种、载体孔结构、贵金属分散度等对催化活性和稳定性的影响机制及优化策略.其次,鉴于化石燃料的日益减少,本文还概述了光热协同催化技术,该技术结合了光催化和热催化技术,通过太阳光的光热转换,能够在较低的温度下高效催化消除VOCs,并介绍了其效率和转化机制.此外,文中还深入分析了H_(2)O,CO_(2)和SO_(2)等气体对催化稳定性的影响机制.最后,考虑到我国当前大气污染防治面临更为复杂的复合污染问题等挑战,对未来发展趋势提出了展望:(1)利用活性空间和活性位点分离策略协同催化净化VOCs和NO_(x),从而实现催化氧化和还原反应的高效进行.(2)聚焦于大气污染物和温室气体的协同处理,探究CO_(2)和VOCs协同转化的路径和效率,为减污降碳和实现碳中和提供新思路.(3)设计合成新型串联催化剂用于安全转化含CVOCs的多组分污染物,以实现VOCs污染广谱性控制.(4)发展先进的原位表征技术(如原位电子显微镜、同位素示踪技术、原位拉曼光谱、原位X射线光电子能谱等)以实时检测催化剂的原子结构变化、吸附VOCs分子降解的中间体变化等,并结合理论计算确定最优反应路径,从而指导催化剂的设计与优化.(5)深入研究外场(例如,光能、电能、磁能)耦合热催化降解VOCs的技术,以期实现反应条件更温和、反应速率更高的催化过程.综上,本文综述了通过实验和理论计算手段揭示催化剂消除VOCs污染的性能与构效关系的研究进展,系统地呈现了治理VOCs污染研究的基本逻辑和框架体系,以期为后续开发高活性、高稳定性和高选择性的催化剂及其工业化应用提供借鉴.

Volatile organic compounds(VOCs)can cause atmospheric environmental problems such as haze and photochemical smog,which seriously restrict the sustainable development of the environment and threaten human health.Effective and comprehensive implementation of VOC prevention is an arduous task.Catalytic oxidation can achieve VOC removal with low energy costs and high efficiency.This review presents representative research progress in thermal or photothermal catalysis over the past ten years,concentrating on various catalysts with distinctive morphologies and structures designed and prepared for investigating single-or multi-component VOC purification,synergetic elimination of VOCs and NO_(x),and VOCs resource utilization.Furthermore,the influence mechanisms of H_(2)O,CO_(2),and SO_(2)on the catalytic stability are summarized.The activity and stability of the catalysts affect their lifespan and cost of use.In particular,for supported noble-metal catalysts with poor stability,some unique design strategies have been summarized for the efficient removal of VOCs while balancing low noble-metal usage and optimized catalytic performance.Finally,the scientific problems and future research directions are presented.Coordinated treatment of atmospheric pollutants and greenhouse gases should be considered.This study is expected to provide profound insights into the design of catalysts with high activity,selectivity,and stability,as well as air pollution control via catalytic methods.