Abstract
An environmentally-benign way of producing hydrogen is methane decomposition. This study focused on methane decomposition using Fe and Fe-Ni catalysts, which were dispersed over different supports by the wet-impregnation method. We observed the effect of modifying ZrO(2)with La(2)O(3)and WO(3)in terms of H(2)yield and carbon deposits. The modification led to a higher H(2)yield in all cases and WO3-modified support gave the highest yield of about 90% and was stable throughout the reaction period. The reaction conditions were at 1 atm, 800 degrees C, and 4000 mL(hg(cat))(-1)space velocity. Adding Ni to Fe/x-ZrO(2)gave a higher H(2)yield and stability for ZrO(2)and La2O3+ ZrO2-supported catalysts whose prior performances and stabilities were very poor. Catalyst samples were analyzed by characterization techniques like X-ray diffraction (XRD), nitrogen physisorption, temperature-programmed reduction (TPR), thermo-gravimetric analysis (TGA), and Raman spectroscopy. The phases of iron and the supports were identified using XRD while the BET revealed a significant decrease in the specific surface areas of fresh catalysts relative to supports. A progressive change in Fe's oxidation state from Fe(3+)to Fe(0)was observed from the H-2-TPR results. The carbon deposits on Fe/ZrO(2)and Fe/La2O3+ ZrO(2)are mainly amorphous, while Fe/WO3+ ZrO(2)and Fe-Ni/x-ZrO(2)are characterized by graphitic carbon.