H2 generation from two-step thermochemical water-splitting reaction using sol-gel derived SnxFeyOz

H-2 has a great potential to replace fossil fuels and contribute to clean energy by reducing the environmental carbon foot-print. This study reports H-2 generation from a thermochemical water-splitting reaction using sol-gel derived SnxFeyOz powders. The sol-gel synthesis involved the addition of SnCl2 center dot 2H(2)O and FeCl2 center dot 4H(2)O in ethanol followed by gelation using propylene oxide. As-synthesized gels were aged, dried, and heated rapidly upto different temperatures and quenched in air or N-2 environment. The calcined powders were characterized using powder x-ray diffraction, BET surface area analyzer, and scanning electron microscopy (SEM). Calcination temperature and environment were found to have a significant effect on phase composition and specific surface area (SSA). The calcined SnxFeyOz powders were placed in a tubular Inconel reactor and four consecutive thermochemical cycles were performed. Water-splitting and regeneration steps were carried out at 900 degrees C and 1100 degrees C, respectively. The powder calcined in N-2 environment showed a mixed phase composition containing Sn0.4Fe2.6O4 and SnO2 and it generated an average of 1.88 ml of H-2 g(-1) cycle(-1). (C) 2011 American Institute of Physics. [doi: 10.1063/1.3659684]