La1-xSrxMO3 (M = Mn, Fe) perovskites as materials for thermochemical hydrogen production in conventional and membrane reactors

La1-xSrxMO3 (M = Mn, Fe) perovskites are investigated as potential redox materials for the thermochemical production of hydrogen. Thermogravimetric oxidation/reduction experiments indicated that the materials are able to lose and uptake oxygen reversibly from their lattice up to 5.5 wt.% for La1-xSrxMO3 with x = 1 and up to 1.7 wt.% for La1-xSrxFeO3 With x = 0. Pulse reaction experiments indicated that the materials can be used as redox catalysts in a redox process where water is dissociated giving rise to the production of pure hydrogen during the oxidation step. The oxidation and reduction steps can be combined in a membrane reactor constructed from dense perovskite membranes towards a continuous and isothermal operation. The system is also able to operate on partial pressure-based desorption without the need of a carbon-containing reductant, so that a process towards hydrogen production, based only on renewable hydrogen source such as water, can be established. At steady state and 900 degrees C, 25 +/- 7 cm(3) (STP) H-2 m(-2) min(-1) is produced in purified state. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.