Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Natural Resources and Environmental Science, Zhejiang University , 310058 Hangzhou, P. R. China.
Zhejiang Provincial Engineering Research Centre of Industrial Boiler & Furnace Flue Gas Pollution Control, 388 Yuhangtang Road, 310058 Hangzhou, P. R. China.
Environ Sci Technol. 2017 Jul 18;51(14):8057-8066. doi: 10.1021/acs.est.6b06585. Epub 2017 Jun 30.
Industrial-use catalysts usually encounter severe deactivation after long-term operation for catalytic oxidation of chlorinate volatile organic compounds (CVOCs), which becomes a "bottleneck" for large-scale application of catalytic combustion technology. In this work, typical acidic solid-supported catalysts of MnCeO/HZSM-5 were investigated for the catalytic oxidation of chlorobenzene (CB). The activation energy (E), Brønsted and Lewis acidities, CB adsorption and activation behaviors, long-term stabilities, and surficial accumulation compounds (after aging) were studied using a range of analytical techniques, including XPS, H-TPR, pyridine-IR, DRIFT, and O-TP-Ms. Experimental results revealed that the Brønsted/Lewis (B/L) ratio of MnCeO/HZSM-5 catalysts could be adjusted by ion exchange of H• (in HZSM-5) with Mn (where the exchange with Ce did not distinctly affect the acidity); the long-term aged catalysts could accumulate ca. 14 organic compounds at surface, including highly toxic tetrachloromethane, trichloroethylene, tetrachloroethylene, o-dichlorobenzene, etc.; high humid operational environment could ensure a stable performance for MnCeO/HZSM-5 catalysts; this was due to the effective removal of Cl• and coke accumulations by HO washing, and the distinct increase of Lewis acidity by the interaction of HO with HZSM-5. This work gives an in-depth view into the CB oxidation over acidic solid-supported catalysts and could provide practical guidelines for the rational design of reliable catalysts for industrial applications.
工业用催化剂在用于催化氧化氯代挥发性有机化合物 (CVOCs) 时，通常会在长期运行后严重失活，这成为催化燃烧技术大规模应用的“瓶颈”。在这项工作中，研究了典型的酸性固载型 MnCeO/HZSM-5 催化剂用于催化氧化氯苯 (CB)。使用一系列分析技术，包括 XPS、H-TPR、吡啶-IR、DRIFT 和 O-TP-Ms，研究了催化剂的活化能 (E)、Brønsted 和 Lewis 酸度、CB 吸附和活化行为、长期稳定性以及表面积累化合物（老化后）。实验结果表明，MnCeO/HZSM-5 催化剂的 Brønsted/Lewis (B/L) 比可以通过 H•（在 HZSM-5 中）与 Mn 的离子交换进行调节（Ce 的交换对酸度没有明显影响）；老化后的长期催化剂可以在表面上积累约 14 种有机化合物，包括高毒性的四氯化碳、三氯乙烯、四氯乙烯、邻二氯苯等；高湿操作环境可以确保 MnCeO/HZSM-5 催化剂的稳定性能；这是由于 HO 洗涤有效去除了 Cl•和焦炭积聚，并且 HO 与 HZSM-5 的相互作用明显增加了 Lewis 酸度。这项工作深入了解了酸性固载型催化剂上的 CB 氧化反应，并可为工业应用中可靠催化剂的合理设计提供实用指导。
