The present paper deals with the catalytic decomposition of sulfuric acid reaction which is common to several sulfur based thermochemical water splitting cycles including the sulfur-iodine thermochemical cycle. The activity and stability of Cr substituted Fe oxide catalysts were studied for the sulfuric acid decomposition reaction. The samples Fe2(1-x)Cr2xO3 were synthesized using ceramic route and characterized by XRD, N-2-BET and IR spectroscopy. The stability of catalysts toward repeated reduction-oxidation cycle was monitored by recording multiple TPR/TPO profiles. The temperature dependent activity was evaluated using gas chromatography in temperature range of 400-800 degrees C for the sulfuric acid decomposition reaction having a feed rate of space velocity of 1200 ml g(-1) h(-1). The SO2 in the effluent gases was identified by IR and mass spectrometry. The mechanism involves the formation of metastable metal sulfate (M-SO4) on the surface of oxides during SO3 -> SO2 conversion as suggested by XRD and IR studies on used Fe2(1-x)Cr2xO3 samples. (C) 2007 International Association for Hydrogen Energy.