N2O Utilization as a Soft Oxidant for the Catalytic Synthesis of Styrene from Ethylbenzene over Ce-Co/CNTs Catalyst

The use of nitrous oxide (N2O) as a soft oxidant for the synthesis of styrene (ST) from ethylbenzene (EB) is a promising technique for obtaining the desired product while eliminating greenhouse gas emission. In this study, carbon nanotubes (CNTs) supported CeO2-Co3O4 binary oxides were synthesized via a hydrothermal method and evaluated as the catalyst for the oxidative dehydrogenation of ethylbenzene with N2O. The Ce/Co molar ratio was found to have a considerable effect on the structural and textural properties of the CNTs, and the 0.10Ce-20wt%Co/CNTs exhibited a high catalytic performance, with a 41% conversion of EB and an 84% selectivity toward ST. Characterization results showed that there existed strong interactions between Co and Ce species on CNTs surface, which not only decreased the crystallite size of the cobalt oxide spinel, but also resulted in more distortion of CeO2 crystal lattice, thereby weakening the Ce-O bond. Moreover, the good reducibility of 0.10Ce-20wt%Co/CNTs was responsible for the generation of active oxygen and the suitable acidity avoided the dealkylation reactions. Additionally, the high Co3+/Co2+ ratio favored EB dehydrogenation, and the transformation of Ce4+/Ce3+ accelerated the transfer of oxygen, replenishing the oxygen vacancy, thus prompting the entire reaction. [GRAPHICS] .

Automated summary

In this study, CeO2-Co3O4 binary oxide catalysts supported on carbon nanotubes (CNTs) were synthesized and evaluated for the oxidative dehydrogenation of ethylbenzene with N2O. The best catalyst, 0.10Ce-20wt%Co/CNTs, exhibited high catalytic activity and selectivity, which can be attributed to the strong interaction between Co and Ce species on CNTs surface, good reducibility, and suitable acidity.