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- Title
Efficient Oxidative Dehydrogenation of Ethylbenzene over K/CeO 2 with Exceptional Styrene Yield.
- Authors
Sun, He; Zhang, Juping; Li, Kongzhai; Wang, Hua; Zhu, Xing
- Abstract
Highlights: What are the main findings? A styrene yield of 91.4% was found for 10% k/CeO2 at 500 °C and CO2-O2 mixed atmosphere. The excellent catalytic performance of 10% k/CeO2 is attributed to the alkali metal oxide modified cerium oxide and carbon dioxide induced oxygen vacancies to promote the dehydrogenation of ethylbenzene. What is the implication of the main finding? The proposed ODH strategy by using oxygen vacancies enriched catalysts offers an important insight into the efficient dehydrogenation of ethylbenzene at mild conditions. Oxidative dehydrogenation (ODH) is an alternative for styrene (ST) production compared to the direct dehydrogenation process. However, ODH with O2 or CO2 suffers from either over-oxidation or endothermic property/low ethylbenzene conversion. Herein, we proposed an ODH process with a CO2-O2 mixture atmosphere for the efficient conversion of ethylbenzene (EB) into styrene. A thermoneutral ODH is possible by the rationalizing of CO2/O2 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/CeO2 achieved the highest ethylbenzene dehydrogenation activity due to the enhanced oxygen mobility and CO2 adsorbability. The catalyst achieved 90.8% ethylbenzene conversion and 97.5% styrene selectivity under optimized conditions of CO2-4O2 oxidation atmosphere, a temperature of 500 °C, and a space velocity of 5.0 h−1. It exhibited excellent catalytic and structural stability during a 50 h long-term test. CO2 induces oxygen vacancies in ceria and promotes oxygen exchange between gaseous oxygen and ceria. The ethylbenzene dehydrogenation in CO2-O2 follows a Mars-van Krevelen (MvK) reaction mechanism via Ce3+/Ce4+ 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.
- Subjects
OXIDATIVE dehydrogenation; ETHYLBENZENE; STYRENE; CERIUM oxides; ALKALI metals; CARBON dioxide
- Publication
Catalysts (2073-4344), 2023, Vol 13, Issue 4, p781
- ISSN
2073-4344
- Publication type
Article
- DOI
10.3390/catal13040781