Enhancement of plasma-catalytic oxidation of ethylene oxide (EO) over Fe-Mn catalysts in a dielectric barrier discharge reactor

In this work, an integrated system combining non-thermal plasma (NTP) and Fe-Mn catalysts was developed for ethylene oxide (EO) oxidation. The effect of Fe/Mn molar ratio on the oxidation rate of EO and energy yield of the plasma-catalytic process has been investigated as a function of specific energy density (SED). Compared with the case of using plasma alone, the combination of plasma and Fe-Mn catalysts greatly enhanced the reaction performance by the factor of 25.2% to 97.6%. The maximum oxidation rate of 98.8% was achieved when Fe1Mn1 catalyst was placed in the dielectric barrier discharge (DBD) reactor at the SED of 656.1 J.L-1. The highest energy yield of 2.82 g.kWh(-1) was obtained at the SED of 323.2 J.L-1 over the Fe1Mn1 catalyst. The interactions between Fe and Mn species resulted in larger specific surface area of the catalyst. Moreover, the reducibility of the catalysts was improved, while more surface adsorbed oxygen (Oads) was detected on the catalyst surfaces. Moreover, the redox cycles between Fe and Mn species facilitated consumption and supplementation of reactive oxygen species, which contributed to the plasma-catalytic oxidation reactions. The major reaction products of plasma-induced EO oxidation over the Fe-Mn catalysts, including CH3COOH, CH3CHO, CH4, C2H6 and C2H4, were observed using the FT-IR analyzer and GC-MS instrument. The reaction mechanisms of EO oxidation were discussed in terms of both gas-phase reaction and catalyst surface reaction. The redox cycles between Fe and Mn species facilitated the plasma reaction and accelerated the deep oxidation of by-products. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

An integrated system combining non-thermal plasma and Fe-Mn catalysts was developed for ethylene oxide oxidation, showing significantly enhanced reaction performance compared to using plasma alone. The interactions between Fe and Mn species led to improved catalyst properties, contributing to the oxidation reactions. Redox cycles between Fe and Mn species facilitated plasma reactions and accelerated the deep oxidation of by-products, leading to the production of key reaction products including acetic acid, acetaldehyde, methane, ethane, and ethylene.