Oxidative dehydrogenation of ethylbenzene to styrene with CO2over Al‐MCM‐41‐supported vanadia catalysts
Oxidative dehydrogenation of ethylbenzene to styrene with CO2over Al‐MCM‐41‐supported vanadia catalysts
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DOI：
10.1002/aoc.5396
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发表时间：
2019-12
影响因子：
3.9
通讯作者：
Shuwei Chen;Zheqi Xu;D. Tan;Dahai Pan;X. Cui;Yan Qiao;Ruifeng Li
中科院分区：
文献类型：
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作者：
Shuwei Chen;Zheqi Xu;D. Tan;Dahai Pan;X. Cui;Yan Qiao;Ruifeng Li
考察了不同V负载量的Al-MCM-41负载型钒催化剂(V/Al-MCM-41)对CO_2氧化乙苯脱氢合成苯乙烯(ST)的催化性能。作为对比，还使用了纯二氧化硅MCM-41作为钒催化剂的载体。采用氮气吸附、X-射线衍射法(XRD)、傅立叶变换红外光谱、程序升温还原、热重分析(TGA)、紫外拉曼光谱、漫反射(DR)光谱等手段对催化剂进行了表征。结果表明，催化剂的催化性能和V物种的性质强烈地依赖于V的负载量和载体的性质。与MCM-41负载的催化剂相比，Al-MCM-41负载的钒催化剂表现出更高的催化活性和稳定性以及高的ST选择性(>；98%)。目前V/Al-MCM-41催化剂的优异催化性能归因于Al-MCM-41载体更有利于V物种的高分散和活性V5+物种的稳定。结合X射线衍射仪、热重分析和紫外可见光谱的表征结果表明，CO2-ODEB过程中V5+被深度还原为V3+是负载型钒催化剂失活的主要原因，而积炭对催化剂稳定性的影响不大。
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 N2adsorption, 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.