This study demonstrates the merits of coupling non-thermal plasma (NTP) with supported metal sulfide catalysts for SO2 reduction using CH4 and H2 in a dielectric barrier discharge (DBD) reactor. Similarly, SO2 reaction with CO2 was examined. Different metal sulfides (Cr, Mo, Fe, Co, Ni) supported on Al2O3 were investigated. Catalysts showed no activity without plasma under the reaction condition (150 °C and 1 atm). On the other hand, plasma discharge alone exhibited some activity for SO2 conversion (21%, 6.7%, and 2% using CH4, H2, and CO2, respectively), but with relatively low selectivity to elemental sulfur. Furthermore, no SO2 conversion was attainable without the addition of a proper co-reactant. The combination of metal sulfides and NTP results in synergetic effects where plasma activates the catalyst, thus improving SO2 conversion, while the catalyst enhances sulfur selectivity (&gt;95%). The use of CH4 as a reducing agent produces several byproducts (i.e., CO2, CO, H2, H2O, H2S, ethane, ethylene, and propane) indicating complex multi-reaction pathways. Metal sulfide catalysts not only enhance SO2 and CH4 conversion but also selectivity toward hydrocarbons; for example, FeS(10)/Al2O3 improved SO2 and CH4 conversion by 55% and 48% respectively, as well as hydrocarbon selectivity by 160% compared to alumina support alone. This research clearly shows the major advantages of combining NTP and a sulfide catalyst for SO2 reduction.

Cold plasma catalysis for SO2 reduction with CH4 over metal sulfide catalysts

2019 Spring National Meeting

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