Enhanced performance for plasma-catalytic oxidation of 1 ethyl acetate over La 1x Ce x CoO 3 + δ catalysts

29 In this work, plasma-catalytic oxidation of low concentration ethyl acetate (100 ppm) over 30 La1-xCexCoO3+δ (x=0, 0.05, 0.1, 0.3 and 0.5) perovskite catalysts was carried out in a coaxial 31 dielectric barrier discharge (DBD) reactor. The effects of Ce-doping on the removal of ethyl 32 acetate and COx selectivity in the plasma-catalytic oxidation process were investigated as a 33 function of specific energy density (SED). Compared to the plasma reaction without a catalyst, 34 the presence of the LaCoO3 catalyst in the plasma enhanced the removal of ethyl acetate and 35 COx selectivity. The use of the Ce-doped catalysts further enhanced the performance of the 36 plasma-catalytic oxidation process. The highest removal efficiency of ethyl acetate (100%) 37 and COx selectivity (91.8%) were achieved in the plasma-catalytic oxidation of ethyl acetate 38 over the La0.9Ce0.1CoO3+δ catalyst at a SED of 558 JL. The interactions between Ce and 39 LaCoO3 resulted in an increased specific surface area (by 17.1% to 62.9%) and a reduced 40 crystallite size (by 13.5%-68.2%) of the Ce-doped LaCoO3 catalysts compared to pure 41 LaCoO3, which favours the oxidation of ethyl acetate in the plasma process. Compared to the 42 LaCoO3 catalyst, the Ce-doped perovskite catalysts showed higher content (maximum 54.9%) 43 of surface adsorbed oxygen (Oads) and better reducibility, both of which significantly 44 contributed to the enhanced oxidation of ethyl acetate and intermediates in the 45 plasma-assisted surface reactions. The coupling of plasma with the Ce-doped catalysts also 46 reduced the formation of by-products including NO2 and N2O. The possible reaction pathways 47 involved in the plasma oxidation process have been discussed. 48 49