Structural, electrical and transport properties of iron doped calcium titanates in view of applications for hydrogen production through the electrochemical conversion of water

Abstract

The present work aims at the investigation of the structural, electrical and transport properties of a series of iron doped calcium titanates (CaTi1-xFexO3-δ) as membrane material for hydrogen production through the electrochemical conversion of water. The ceramic membranes were synthesized according to the conventional solid state reaction technique and their electrical conductivity was examined in a wide range of oxygen partial pressures (P?2=0.21-10-17 atm) at 1173 K, as well as in a wide range of temperatures at P?2=10-7 atm, where they are pure ionic conductors. Among the investigated samples CaTi0.8Fe0.2O3-δ presented the highest ionic conductivity values. Therefore, the oxygen permeability and the hydrogen availability of the specific ceramic membrane were investigated by the method of the high-temperature electrochemical reforming in (1-x)H2+xH2O gas mixtures at the oxygen partial pressure range of 10-20<Po2, atm<10-13 at 1173 K.