Materials for a high temperature coal-based process to produce electrolytically pure hydrogen

Abstract

A unique process to produce electrolytically pure hydrogen in a chemically driven cell requires a ceramic membrane material with special properties. Under specific high temperature (800°C-1000°C) and low oxygen pressure (between 10-12 atm and 10-20 atm) conditions, the material must conduct both oxygen ions and electrons, be thermally and chemically stable, and capable of fabrication as a thin gas-tight membrane. A wide variety of materials were synthesized and evaluated for this application, including fluorite structure oxides based on both Ce02 and Y203-stabilized Zr02, perovskite-related oxides, and Bi 203-based materials.