Abstract
Natural gas resources, stimulate the method of catalytic methane decomposition. Hydrogen is a superb energy carrier and integral component of the present energy systems, while carbon nanotubes exhibit remarkable chemical and physical properties. The reaction was run at 700 degrees C in a fixed bed reactor. Catalyst calcination and reduction were done at 500 degrees C. MgO, TiO2 and Al2O3 supported catalysts were prepared using a co-precipitation method. Catalysts of different iron loadings were characterized with BET, TGA, XRD, H-2-TPR and TEM. The catalyst characterization revealed the formation of multi-walled nanotubes. Alternatively, time on stream tests of supported catalyst at 700 degrees C revealed the relative profiles of methane conversions increased as the % Fe loading was increased. Higher % Fe loadings decreased surface area of the catalyst. Iron catalyst supported with Al2O3 exhibited somewhat higher catalytic activity compared with MgO and TiO2 supported catalysts when above 35% Fe loading was used. CH4 conversion of 69% was obtained utilizing 60% Fe/Al2O3 catalyst. Alternatively, Fe/MgO catalysts gave the highest initial conversions when iron loading below 30% was employed. Indeed, catalysts with 15% Fe/MgO gave 63% conversion and good stability for 1 h time on stream. Inappropriateness of Fe/TiO2 catalysts in the catalytic methane decomposition was observed.