Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO<sub>2</sub> with Exceptional Styrene Yield
Oxidative dehydrogenation (ODH) is an alternative for styrene (ST) production compared to the direct dehydrogenation process. However, ODH with O<sub>2</sub> or CO<sub>2</sub> suffers from either over-oxidation or endothermic property/low ethylbenzene conversion. Herein, we p...
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MDPI AG
2023-04-01
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| Online Access: | https://www.mdpi.com/2073-4344/13/4/781 |
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| author | He Sun Juping Zhang Kongzhai Li Hua Wang Xing Zhu |
| author_facet | He Sun Juping Zhang Kongzhai Li Hua Wang Xing Zhu |
| author_sort | He Sun |
| collection | DOAJ |
| description | Oxidative dehydrogenation (ODH) is an alternative for styrene (ST) production compared to the direct dehydrogenation process. However, ODH with O<sub>2</sub> or CO<sub>2</sub> suffers from either over-oxidation or endothermic property/low ethylbenzene conversion. Herein, we proposed an ODH process with a CO<sub>2</sub>-O<sub>2</sub> mixture atmosphere for the efficient conversion of ethylbenzene (EB) into styrene. A thermoneutral ODH is possible by the rationalizing of CO<sub>2</sub>/O<sub>2</sub> molar ratios from 0.65 to 0.66 in the temperature range of 300 to 650 °C. K modification is favorable for ethylbenzene dehydrogenation, and 10%K/CeO<sub>2</sub> achieved the highest ethylbenzene dehydrogenation activity due to the enhanced oxygen mobility and CO<sub>2</sub> adsorbability. The catalyst achieved 90.8% ethylbenzene conversion and 97.5% styrene selectivity under optimized conditions of CO<sub>2</sub>-4O<sub>2</sub> oxidation atmosphere, a temperature of 500 °C, and a space velocity of 5.0 h<sup>−1</sup>. It exhibited excellent catalytic and structural stability during a 50 h long-term test. CO<sub>2</sub> induces oxygen vacancies in ceria and promotes oxygen exchange between gaseous oxygen and ceria. The ethylbenzene dehydrogenation in CO<sub>2</sub>-O<sub>2</sub> follows a Mars-van Krevelen (MvK) reaction mechanism via Ce<sup>3+</sup>/Ce<sup>4+</sup> redox pairs. The proposed ODH strategy by using oxygen vacancies enriched catalysts offers an important insight into the efficient dehydrogenation of ethylbenzene at mild conditions. |
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| spelling | doaj.art-fb4b8f658dc44041bb6ee6afa0c37d592023-11-17T18:42:28ZengMDPI AGCatalysts2073-43442023-04-0113478110.3390/catal13040781Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO<sub>2</sub> with Exceptional Styrene YieldHe Sun0Juping Zhang1Kongzhai Li2Hua Wang3Xing Zhu4State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, ChinaState Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, ChinaState Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, ChinaState Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, ChinaState Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, ChinaOxidative dehydrogenation (ODH) is an alternative for styrene (ST) production compared to the direct dehydrogenation process. However, ODH with O<sub>2</sub> or CO<sub>2</sub> suffers from either over-oxidation or endothermic property/low ethylbenzene conversion. Herein, we proposed an ODH process with a CO<sub>2</sub>-O<sub>2</sub> mixture atmosphere for the efficient conversion of ethylbenzene (EB) into styrene. A thermoneutral ODH is possible by the rationalizing of CO<sub>2</sub>/O<sub>2</sub> molar ratios from 0.65 to 0.66 in the temperature range of 300 to 650 °C. K modification is favorable for ethylbenzene dehydrogenation, and 10%K/CeO<sub>2</sub> achieved the highest ethylbenzene dehydrogenation activity due to the enhanced oxygen mobility and CO<sub>2</sub> adsorbability. The catalyst achieved 90.8% ethylbenzene conversion and 97.5% styrene selectivity under optimized conditions of CO<sub>2</sub>-4O<sub>2</sub> oxidation atmosphere, a temperature of 500 °C, and a space velocity of 5.0 h<sup>−1</sup>. It exhibited excellent catalytic and structural stability during a 50 h long-term test. CO<sub>2</sub> induces oxygen vacancies in ceria and promotes oxygen exchange between gaseous oxygen and ceria. The ethylbenzene dehydrogenation in CO<sub>2</sub>-O<sub>2</sub> follows a Mars-van Krevelen (MvK) reaction mechanism via Ce<sup>3+</sup>/Ce<sup>4+</sup> redox pairs. The proposed ODH strategy by using oxygen vacancies enriched catalysts offers an important insight into the efficient dehydrogenation of ethylbenzene at mild conditions.https://www.mdpi.com/2073-4344/13/4/781ethylbenzeneoxidative dehydrogenationceriaCO<sub>2</sub> |
| spellingShingle | He Sun Juping Zhang Kongzhai Li Hua Wang Xing Zhu Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO<sub>2</sub> with Exceptional Styrene Yield Catalysts ethylbenzene oxidative dehydrogenation ceria CO<sub>2</sub> |
| title | Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO<sub>2</sub> with Exceptional Styrene Yield |
| title_full | Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO<sub>2</sub> with Exceptional Styrene Yield |
| title_fullStr | Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO<sub>2</sub> with Exceptional Styrene Yield |
| title_full_unstemmed | Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO<sub>2</sub> with Exceptional Styrene Yield |
| title_short | Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO<sub>2</sub> with Exceptional Styrene Yield |
| title_sort | efficient oxidative dehydrogenation of ethylbenzene over k ceo sub 2 sub with exceptional styrene yield |
| topic | ethylbenzene oxidative dehydrogenation ceria CO<sub>2</sub> |
| url | https://www.mdpi.com/2073-4344/13/4/781 |
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