Structure dependence of the enhanced sulfur tolerance of core-shell CoMn oxides for benzene oxidation: Discrepant sulfur species and less affected reactant activation

文献类型： 外文期刊

第一作者： Liu, Yang

作者： Liu, Yang;Cheng, Lin;Zhang, Di;Zhan, Jingjing;Shan, Jiajia;Zhou, Hao;Yi, Xianliang;Li, Zhonghong;Shen, Xudong

作者机构：

关键词： VOCs; Catalytic oxidation; Manganese oxide; Cobalt decoration; Sulfur resistance

期刊名称：SEPARATION AND PURIFICATION TECHNOLOGY （ 影响因子：9.0； 五年影响因子：8.5 ）

ISSN： 1383-5866

年卷期： 2025 年 358 卷

页码：

收录情况： SCI

摘要： Effective reduction of VOCs emissions in practical gas requires low-temperature catalysts with remarkable SO2 tolerance. Here via simply mixing CoCO3 into the precursors of alpha-MnO2, a core-shell CoMn composite was developed. The leading one with CoCO3 addition of 3 g (Co3Mn) achieved 100 % C6H6-to-CO2 conversion at >= 250 degrees C under 120 L/g/h, and still the CO2 yield over the sulfurized Co3Mn (simulated by H2SO3 vapor pretreatment) was maintained 100 %. However, with respect to the case of fresh MnO2, the CO2 production at 250 and 300 degrees C over the sulfurized MnO2 was decreased by 26 % and 8 %, respectively, and in the meantime, a larger amount of CO was detected. The dominant formation of abundant MnSO4 species due to sulfur poisoning led to the deactivation of pure MnO2, while over Co3Mn the formation of MnSO4 was significantly inhibited because of (i) the electron transfer from Co2+ to Mn4+ restraining that from S4+ to Mn4+ and (ii) the stronger alkalinity of Co species making the acidic H2SO3 preferentially anchor on Co as CoSO4. Along with the sacrificial role, another way cobalt alleviated sulfate toxicity was through transiting the aggregated sulfate deposition into scattered state. Investigations conducted primarily with UV-vis DRS and temperature-programmed techniques further reveal that neither MnO2 nor Co3Mn could escape from the sulfur-induced adversity on activation of O2 and benzene, but the sulfurized Co3Mn was much less affected, thus sustaining the deep benzene oxidation. Finally, reaction routes were unraveled according to the phenol, benzoquinone, maleic acid and acetic acid intermediates.

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