OH- ion transport in hydrated layered perovskite LaSr3Fe3O8(OH)2∙xH2O in the middle temperature range

Abstract Layered perovskite LaSr3Fe3O10 (LSF) shows hydration characterized by the water vapor intercalation and the orientation of hydroxide groups. This study tries to investigate whether the hydrated LSF transports proton or hydroxide ion in the intermediate temperature range of 100-300 °C. The electromotive force (EMF) of the warm-pressed LSF with intercalated H2O and OH- by using a vapor concentration cell showed negative value in the temperature range of 120-200 °C. This is an evidence that the hydrated LSF transport hydroxide ions in the temperature range. The EMF approached to zero with increases in temperatures from 150 °C up to 200 because the hydroxide ions are removed and the hole (Fe4+) concentration increased. The results suppose that greater amount of OH- in LSF improves the hydroxide ion transport.