Hydrogen production aided by new (1-x) SrTi0.5Fe0.5O3-delta-xCe(0.8)(Sm0.8Sr0.2)(0.2)O2-delta(MIEC) composite membranes
In the present work, composite materials of the type (1-x)SrTi0.5Fe0.5O3-delta-xCe(0.8)(Sm0.8Sr0.2)(0.2)O2-delta (with x = 0, 0.25, 0.5, 0.75 and 1) are obtained by the two step solid state technique. Their transport properties are investigated in terms of their usage as mixed ionic-electronic conducting (MIEC) membrane materials for hydrogen production. It is found that, in reducing conditions the composites are characterized by mixed conductivity, which level is controlled by the electrical properties of the prevailing phase. Moreover, at 900 degrees C and pO(2) = 10(-18) atm, total conductivity, ambipolar conductivity and oxygen permeability of composites dramatically grow (each of about 500%), when the fluorite component content x increases from 0 to 1. High-conducting and strengthened material 0.5SrTi(0.5)Fe(0.5)O(3-delta)-0.5Ce(0.8)(Sm0.8Sr0.2)(0.2)O2-delta is chosen for making tube shaped membranes using the tape rolling method, which are successfully applied for hydrogen production in laboratory scale. The hydrogen flux reached 0.176 ml cm(-2) min(-1) for x = 1, T = 900 degrees C and emf = 10 mV. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.