Methanation studies: characterization of some iron catalysts by X-ray diffraction and Curie point determinations

Abstract Methanation studies have been carried out at 290°C in a microreactor with a H 2 CO ratio of 9 1 . The catalysts studied were iron(III) oxide, iron(II) diiron(III) tetroxide, and metallic iron. These were all prepared reproducibly from iron(III) nitrate. The catalysts were characterized by X-ray diffraction and magnetic analysis both at maximum activity and after deactivation. All catalysts at maximum activity contained Fe 5 C 2 . Deactivation of the catalysts was found to be due to excess graphitic carbon. Sustained catalytic activity was found to require the presence of iron(II) diiron(III) tetroxide, probably to serve as a source for continual renewal of the active catalyst surface.