Syngas Formation by Nickel and Iron Catalysts for Partial Oxidation of Methane with Microwave Assistance

In this study, microscale nickel (Ni, 0.33 wt%) and iron (Fe, 0.26 wt%) catalysts coated on cordierite particles were used in the partial oxidation of methane to form syngas by a microwave-assisted process. Microwave treatment can be applied by coupling with materials having higher dielectric loss values. This is because Ni has more electron holes and a higher activity than Fe, and Ni-based catalysts produce heat much faster than Fe-based catalysts upon microwave treatment (208.8 vs 26 degrees C/min). Under the same experimental conditions of a volumetric ratio of CH4/air of 1:1, a microwave output power of 450 W, and the reaction time set to 360 min, higher H-2 and CO yields were obtained with the Ni catalyst than with the Fe catalyst (54.7 vs 46.0% for H-2 and 19.7 vs 14.4% for CO). The coke content was determined to be 0.4 wt% for the Ni catalyst and 0.51 wt% for the Fe catalyst. The shape of the coke was different for the two catalysts; finely shaped coke was observed for the Ni catalyst, whereas thicker multilayered coke appeared on the Fe catalyst.