Tabakova Tatyana
Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Molecules. 2024 Nov 20;29(22):5484. doi: 10.3390/molecules29225484.
Increased levels and detrimental effects of volatile organic compounds (VOCs) on air quality and human health have become an important issue in the environmental field. Benzene is classified as one of the most hazardous air pollutants among non-halogenated aromatic hydrocarbons with toxic, carcinogenic, and mutagenic effects. Various technologies have been applied to decrease harmful emissions from various sources such as petrochemistry, steel manufacturing, organic chemical, paint, adhesive, and pharmaceutical production, vehicle exhausts, etc. Catalytic oxidation to CO and water is an attractive approach to VOC removal due to high efficiency, low energy consumption, and the absence of secondary pollution. However, catalytic oxidation of the benzene molecule is a great challenge because of the extraordinary stability of its six-membered ring structure. Developing highly efficient catalysts is of primary importance for effective elimination of benzene at low temperatures. This review aims to summarize and discuss some recent advances in catalyst composition and preparation strategies. Advantages and disadvantages of using noble metal-based catalysts and transition metal oxide-based catalysts are addressed. Effects of some crucial factors such as catalyst support nature, metal particle size, electronic state of active metal, redox properties, reactivity of lattice oxygen and surface adsorbed oxygen on benzene removal are explored. Thorough elucidation of reaction mechanisms in benzene oxidation is a prerequisite to develop efficient catalysts. Benzene oxidation mechanisms are analyzed based on in situ catalyst characterization, reaction kinetics, and theoretical simulation calculations. Considering the role of oxygen vacancies in improving catalytic performance, attention is given to oxygen defect engineering. Catalyst deactivation due to coexistence of water vapor and other pollutants, e.g., sulfur compounds, is discussed. Future research directions for rational design of catalysts for complete benzene oxidation are provided.
挥发性有机化合物（VOCs）含量的增加及其对空气质量和人体健康的有害影响已成为环境领域的一个重要问题。苯被归类为非卤代芳烃中危害最大的空气污染物之一，具有毒性、致癌性和致突变性。人们已应用各种技术来减少来自石化、钢铁制造、有机化工、油漆、胶粘剂和制药生产、汽车尾气等各种来源的有害排放物。催化氧化生成二氧化碳和水是一种颇具吸引力的VOC去除方法，因为它具有高效率、低能耗且无二次污染的特点。然而，由于苯分子的六元环结构异常稳定，对其进行催化氧化是一项巨大挑战。开发高效催化剂对于在低温下有效消除苯至关重要。本综述旨在总结和讨论催化剂组成及制备策略方面的一些最新进展。阐述了使用贵金属基催化剂和过渡金属氧化物基催化剂的优缺点。探讨了一些关键因素，如催化剂载体性质、金属颗粒尺寸、活性金属的电子态、氧化还原性质、晶格氧和表面吸附氧的反应性对苯去除的影响。深入阐明苯氧化反应机理是开发高效催化剂的前提。基于原位催化剂表征、反应动力学和理论模拟计算对苯氧化机理进行了分析。考虑到氧空位在提高催化性能方面的作用，关注了氧缺陷工程。讨论了水蒸气和其他污染物（如硫化合物）共存导致的催化剂失活问题。提供了用于完全苯氧化的催化剂合理设计的未来研究方向。
