Oxidative dehydrogenation of ethylbenzene to styrene with CO2 over Al-MCM-41-supported vanadia catalysts |
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Authors: | Shuwei Chen Zheqi Xu Dongchen Tan Dahai Pan Xingyu Cui Yan Qiao Ruifeng Li |
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Institution: | 1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024 China;2. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001 China |
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Abstract: | Catalytic performance of Al-MCM-41-supported vanadia catalysts (V/Al-MCM-41) with different V loading was investigated for oxidative dehydrogenation of ethylbenzene to styrene (ST) with CO2 (CO2-ODEB). For comparison, pure silica MCM-41 was also used as support for vanadia catalyst. The catalysts were characterized by N2 adsorption, X-ray diffraction (XRD) pyridine-Fourier-transform infrared spectroscopy, H2-temperature-programmed reduction, thermogravimetric analysis (TGA), UV-Raman, and diffuse reflectance (DR) UV–vis spectroscopy. The results indicate that the catalytic behavior and the nature of V species depend strongly on the V loading and the support properties. Compared with the MCM-41-supported catalyst, the Al-MCM-41-supported vanadia catalyst exhibits much higher catalytic activity and stability along with a high ST selectivity (>98%). The superior catalytic performance of the present V/Al-MCM-41 catalyst can be attributed to the Al-MCM-41 support being more favorable for the high dispersion of V species and the stabilization of active V5+ species. Together with the characterization results of XRD, TGA, and DR UV–Vis spectroscopy, the deep reduction of V5+ into V3+ during CO2-ODEB is the main reason for the deactivation of the supported vanadia catalyst, while the coke deposition has a less important impact on the catalyst stability. |
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Keywords: | Al-MCM-41 carbon dioxide catalyst deactivation ethylbenzene dehydrogenation vanadium oxide |
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