H 2 generation from two-step thermochemical water-splitting reaction using sol-gel derived Sn xFe yO z

Abstract

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 Sn xFe yO z powders. The sol-gel synthesis involved the addition of SnCl 2 2H 2O and FeCl 2 4H 2O 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 Sn xFe yO z 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 C and 1100 C, respectively. The powder calcined in N 2 environment showed a mixed phase composition containing Sn 0.4Fe 2.6O 4 and SnO 2 and it generated an average of 1.88ml of H 2 g -1 cycle -1. © 2011 American Institute of Physics.