Superior performance of K/Co2AlO4 catalysts for the oxidative dehydrogenation of ethylbenzene to styrene with N2O as an oxidant

This study explored the feasibility of coupling N2O decomposition with ethylbenzene (EB) oxidative dehydrogenation, as an alternative approach for greenhouse gas elimination and styrene (ST) production, on the Co-Al mixed oxides and K-modified catalysts. It was found that N2O could decompose completely over the K/Co2AlO4 catalyst, accompanied with 62.0% of EB conversion and 85.1% of styrene selectivity, which were much better than the existing catalyst systems for EB oxidative dehydrogenation. Characterization results showed that despite the decreased specific surface area of the catalysts with increasing the Co/Al molar ratio, the improved reducibility, the reduced acid properties as well as the higher ratio of Co3+/Co2+ were responsible for the enhanced performance. The K modification not only changed the electronic properties of active metal, resulting from the charge transfer from K cation to the Co species, but also weakened the binding energy of Co3+-O-, leading to the complete decomposition of N2O. Furthermore, the optimized strong acid properties inhibited the dealkylation or ring-opening reactions and significantly reduced the coke deposition on the catalyst surface, thus improving the ST selectivity. (C) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

This study explored the feasibility of coupling N2O decomposition with ethylbenzene oxidative dehydrogenation and found that the K/Co2AlO4 catalyst could achieve complete N2O decomposition with improved EB conversion and styrene selectivity. The modified catalysts showed enhanced performance due to improved reducibility, reduced acid properties, and electron transfer from K cation to Co species.