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Efficient Selective Oxidation of Aromatic Alkanes by Double Cobalt Active Sites over Oxygen Vacancy-rich Mesoporous Co3O4 |
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| Authors: | Yali Liu Yuenan Zheng Danyang Feng Liangliang Zhang Ling Zhang Xiaowei Song Prof Zhen-An Qiao |
| Institution: | 1. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin, 130012 China
Department of Chemical Engineering, School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan, Zhejiang, 316022 China These authors contributed equally to this work.;2. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin, 130012 China State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, Liaoning, 116081 China These authors contributed equally to this work.;3. Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education, Northeast Normal University, Jilin, 130024 China;4. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin, 130012 China;5. State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin, 130012 China |
| Abstract: | The development of efficient catalyst for selective oxidation of hydrocarbon to functional compounds remains a challenge. Herein, mesoporous Co3O4 (mCo3O4-350) showed excellent catalytic activity for selective oxidation of aromatic-alkanes, especially for oxidation of ethylbenzene with a conversion of 42 % and selectivity of 90 % for acetophenone at 120 °C. Notably, mCo3O4 presented a unique catalytic path of direct oxidation of aromatic-alkanes to aromatic ketones rather than the conventional stepwise oxidation to alcohols and then to ketones. Density functional theory calculations revealed that oxygen vacancies in mCo3O4 activate around Co atoms, causing electronic state change from Co3+(Oh)→Co2+(Oh). Co2+(Oh) has great attraction to ethylbenzene, and weak interaction with O2, which provide insufficient O2 for gradual oxidation of phenylethanol to acetophenone. Combined with high energy barrier for forming phenylethanol, the direct oxidation path from ethylbenzene to acetophenone is kinetically favorable on mCo3O4, sharply contrasted to non-selective oxidation of ethylbenzene on commercial Co3O4. |
| Keywords: | Heterogeneous Catalysis Hydrocarbons Oxidation Oxidation Route Oxygen Vacancy |