| 摘要: |
| 甲苯是最具代表的挥发性有机物（VOCs）之一，是PM2.5和臭氧的前驱体，对人体呼吸系统和中枢神经系统有一定的损害，甲苯的去除可以有效地减轻大气环境污染问题和对人体健康的影响。锰基氧化物催化燃烧具有成本低、效率高、稳定性强和氧化还原性能良好等优点，成为治理甲苯的热点。用于甲苯去除的锰基催化剂的种类主要有单一锰氧化物、复合锰氧化物、负载型锰氧化物、钙钛矿型锰氧化物和整体锰氧化物五种。本文以甲苯催化氧化为目标，综述了以上五种锰基催化剂的性能和反应机理受催化剂种类、晶型、形貌、掺杂、负载等的影响，并对该领域未来的研究方向做出了展望。 |
| 关键词: 锰基氧化物 甲苯 催化燃烧 |
| DOI：10.7515/JEE221017 |
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| 基金项目:国家自然科学基金项目（41877481）；中国科学院地球环境研究所大气化学与物理重点实验室开放基金（KLACP2002）；退化与未利用土地整理工程重点实验室开放基金（SZDJ2019-15）；“中国科学院青年交叉团队”项目 |
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| Research progress on catalytic combustion of toluene with manganese-based oxides |
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CHEN Meijuan, ZHAO Jinghan, WANG Wei, YANG Tongxi, HUANG Yu
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1. School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an 710049, China
2. Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China
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| Abstract: |
| Background, aim, and scope Toluene, as one of the most prevalent volatile organic compounds (VOCs), plays a significant role as a precursor to PM2.5 and ozone formation. Manganese oxide catalytic combustion has gained significant attention in toluene remediation due to its low cost, high efficiency, strong stability, and excellent oxidation-reduction performance. There are five main types of manganese oxide catalysts commonly used for toluene removal: single manganese oxides, Mn-based composite oxides, perovskite manganese oxides, supported Mn oxide and Mn-based monoliths. In this study, focusing on catalytic oxidation of toluene, we provide a comprehensive review of the performance and reaction mechanisms of these five manganese-based catalysts, considering the influence of catalyst type, crystal structure, morphology, compositing, and loading. Materials and methods This study provides a comprehensive review of the research progress on five manganese-based catalysts used for the catalytic combustion of toluene. It also gives an outlook on future research directions in this field. Results This study highlights the influence of crystal structure, morphology, valence state, composite composition, and carrier material. Particularly, the use of Mn-based composite oxides, which involve combining manganese oxides with other metal oxides like cerium oxide, copper oxide, cobalt oxide, among others, offers a synergistic combination of the advantages exhibited by both manganese oxide and the respective metal oxides. These composites demonstrate a remarkable ability to significantly lower combustion temperatures, presenting promising prospects for industrial applications. Discussion The performance of manganese oxides in catalytic combustion of toluene can be enhanced through optimization of the preparation method, incorporation with other metal oxides, and loading onto a suitable carrier. These approaches facilitate the generation of highly valent manganese ions, alteration of morphology, increase in oxygen vacancy and adsorbed oxygen, and increase in the specific surface area. As a result, electron transfer and redox capacity in the catalyst are accelerated, leading to improved toluene degradation performance. The oxidation of toluene by manganese oxides follows the MVK mechanism, but there is still controversy regarding the detailed steps. Conclusions Manganese oxides have significant advantages as catalysts for toluene catalytic combustion, and are considered one of the most promising catalysts for future applications. Recommendations and perspectives (1) Further research is needed to explore the inherent connection between the catalyst’s physicochemical properties and its performance in toluene oxidation. (2) In Mn-based monoliths’ study, the integration of manganese oxides with environmentally friendly and low-cost carriers is emerging as a significant trend in industrial development. (3) In-depth investigations into the reaction mechanisms of toluene combustion. Furthermore, it is essential to improve the catalyst’s resistance to poisoning and find effective solutions for catalyst regeneration. |
| Key words: manganese oxide toluene catalytic combustion |
