Oxidative Dehydrogenation of Ethane with CO2 over Mo/LDO Catalyst: The Active Species of Mo Controlled by LDO

Catalysts

Shuang Li¹  Gengzhe Song¹  Duohua Liao¹  Qi Wang¹  Liang Yang¹ 

[1] School of Chemical Engineering, Northwest University, Xi’an 710069, China;

关键词: ethane;    oxidative dehydrogenation;    molybdenum oxide;    CO₂;    Mo/LDO catalyst;   

DOI  :  10.3390/catal12050493

来源: DOAJ

【 摘 要 】

A series of the layered double oxides supported molybdenum oxide catalysts were synthesized and evaluated in the oxidative dehydrogenation of ethane with CO₂ (CO₂-ODHE). The 22.3 wt% Mo/LDO catalyst delivered a 92.3%selectivity to ethylene and a 7.9% ethane conversion at relatively low temperatures. The molybdenum oxide catalysts were fully characterized by XRD, BET, SEM, TEM, UV–vis, Raman TG, and XPS. Isolated [MoO₄]²⁻ dominated on the surface of the fresh 12.5 wt% Mo/LDO catalyst. With the increase of the Mo content, the Mo species transformed from [MoO₄]²⁻ to [Mo₇O₂₄]⁶⁻ and [Mo₈O₂₆]⁴⁻ on the 22.3 wt% and 30.1 wt% Mo/LDO catalysts, respectively. The redox mechanism was proposed and three Mo species including [MoO₄]²⁻, [Mo₇O₂₄]⁶⁻, and [Mo₈O₂₆]⁴⁻ showed quite different functions in the CO₂-ODHE reaction: [MoO₄]²⁻, with tetrahedral structure, preferred the non-selective pathway; [Mo₇O₂₄]⁶⁻, with an octahedral construction, promoted the selective pathway; and the existence of [Mo₈O₂₆]⁴⁻ reduced the ability to activate ethane. This work provides detailed insights to further understand the relationship between structure–activity and the role of surface Mo species as well as their aggregation state in CO₂-ODHE.

【 授权许可】

Unknown