About 20 nm precursor powders for BaCe0.85Y0.15O3-delta (BCY) were synthesized by combustion method. The nanopowder had about 100 times larger specific volume than sintered BCY. A bi-layered proton conducting membrane having a thick porous BCY substrate and an integrally supported dense BCY thin film were co-fabricated facilely by pressing two layers comprising the precursor powder and its mixture with starch, followed by co-sintering at high temperature. Pt was impregnated into the porous BCY layer matrix as anode catalyst for dehydrogenation of ethane to ethylene. A hydrocarbon solid oxide fuel cell with the BCY thin film electrolyte and Pt electrodes demonstrated high selectivity (90.5%) to ethylene at 36.7% ethane conversion with co-generation of 216 MW cm(-2) electrical energy output at 700 degrees C. The ethane conversion and ethylene selectivity increased with current density. (C) 2009 Elsevier Ltd. All rights reserved.