Published online by Cambridge University Press: 06 February 2015
Cerium oxide is an important electrode material in fuel cells. It has been interconverted in the gaseous phase at high temperatures or in the presence of oxygen and more recently in the solid state by applying an electric field. In the dynamic change that occurs, the migration of oxygen vacancies have been initiated at a critical potential of 2.8 V. We wish to report here an electrochemical method where the conversion of cerium oxides is brought out in aqueous medium where hydrogen ion is assisting the process of conversion. Keeping dissolved oxygen level negligible, the conversion of Ce2O3 to CeO2 occurs at 0.72 V vs saturated calomel electrode (SCE) with hydrogen ion assisting the process and the reversible conversion at 0.15 V (SCE). The hydrogen ion assisted conversion is compared with the solid state conversion that operates on oxygen vacancy creation.