Facet Engineered α-MnO2 for Efficient Catalytic Ozonation of Odor CH3SH: Oxygen Vacancy-Induced Active Centers and Catalytic Mechanism
Facet Engineered α-MnO2 for Efficient Catalytic Ozonation of Odor CH3SH: Oxygen Vacancy-Induced Active Centers and Catalytic Mechanism
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Facet 工程 α-MnO2 用于高效催化臭氧化气味 CH3SH：氧空位诱导的活性中心和催化机制
DOI：
10.1021/acs.est.0c05235
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发表时间：
2020-10-06
影响因子：
11.4
通讯作者：
Lee, Shuncheng
中科院分区：
文献类型：
--
作者：
He, Chun;Wang, Yunchen;Lee, Shuncheng
二氧化锰中的氧空位通常被证明是催化臭氧化的反应位点，通过面工程获得具有丰富氧空位的高活性晶面是提高催化活性的可行方法。在这项研究中，制备了三面工程的α - mno2，并成功地用于催化臭氧氧化制臭CH3SH。合成的310-MnO2对臭氧氧化CH3SH的催化活性优于110-MnO2和100-MnO2，在20 min内对70 ppm的CH3SH的去除率达到100%。XPS、Raman、H-2-TPR和DFT计算结果均证明（310）面具有比其他面更高的表面能，可以表征氧空位的构建，从而促进O3的吸附并活化成中间过氧化物（O2-/O22-）和活性氧(中心点O-2(-)/O-1(2))，消除邻近的CH3SH。原位漫反射红外傅里叶变换光谱（In situ DRIFTS）显示，CH3SH分子在S原子上被化学吸附形成CH3S-， CH3S-在此过程中进一步转化为中间体CH3SO3-，最终氧化为SO42-和CO32-/CO2。由于CH3SH在310-MnO2上通过有效的活性氧空缺循环进行深度氧化，310-MnO2的寿命可延长至2.5 h，活性损失有限，而110-MnO2和100-MnO2在1 h内灭活。本研究加深了对MnO2面工程的理解，提出了一种高效、便携的恶臭污染控制催化剂。
The oxygen vacancy in MnO2 is normally proved as the reactive site for the catalytic ozonation, and acquiring a highly reactive crystal facet with abundant oxygen vacancy by facet engineering is advisable for boosting the catalytic activity. In this study, three facet- engineered alpha-MnO2 was prepared and successfully utilized for catalytic ozonation toward an odorous CH3SH. The as-synthesized 310-MnO2 exhibited superior activity in catalytic ozonation of CH3SH than that of 110-MnO2 and 100-MnO2, which could achieve 100% removal efficiency for 70 ppm of CH3SH within 20 min. The results of XPS, Raman, H-2-TPR, and DFT calculation all prove that the (310) facets possess a higher surface energy than other facets can feature the construction of oxygen vacancies, thus facilitating the adsorption and activate O3 into intermediate peroxide species (O2-/O22-) and reactive oxygen species (center dot O-2(-)/O-1(2)) for eliminating adjacent CH3SH. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) revealed that the CH3SH molecular was chemisorbed on S atom to form CH3S-, which was further converted into intermediate CH3SO3- and finally oxidized into SO42- and CO32-/CO2 during the process. Attributed to the deep oxidation of CH3SH on 310-MnO2 via efficient cycling of active oxygen vacancies, the lifetime of 310-MnO2 can be extended to 2.5 h with limited loss of activity, while 110-MnO2 and 100-MnO2 were inactivated within 1 h. This study deepens the comprehension of facet-engineering in MnO2 and presents an efficient and portable catalyst to control odorous pollution.