Protonic conductivity nanostructured ceramic film with improved resistance to carbon dioxide at elevated temperatures

As a high value product, hydrogen is a clean fuel with zero emission, and thereby its applications alleviate the threat of "Greenhouse effect." From the "hydrogen economy" point of view, the predominant way of producing hydrogen is reforming from fossil fuels. A dense ceramic protonic conductive film can be used to separate hydrogen from other reformed products or syngas in gasification process at high temperatures. However, currently existing ceramic films are proven to severely degrade in CO2-containing environments. In this work, a codoped BaCeO3 material was proposed for better CO2 resistance and higher protonic conductivity. Nanostructured BaCeO3-based film was fabricated from nano-grain feedstock using air plasma spray. The hydrogen permeable film has been demonstrated superior to currently available ceramic protonic films for hydrogen separation in terms of chemical stability, protonic and electronic conductivity, and thermo-mechanical properties in the temperature range of 600-800 degrees C. This work has demonstrated a methodology to improve chemical stability, solid ionic conductivity, as well as good mechanical integrity for a protonic membrane system, using a doping composition technique and incorporating a nanostructured membrane manufacturing process. (c) 2005 Elsevier B.V All rights reserved.