Ceria-supported platinum catalysts were used to produce hydrogen by isobutane steam reforming. The influence of gadolinia, as a trivalent cationic oxide (M2O3) dopant at 0-20%, is investigated here. The gadolinia content in the catalysts did not correlate well with reforming activity. The platinum dispersion ranged from 29 to 38% as measured by the propylene hydrogenation method and it did correlate well with reforming activity.