Y-doped BaCeO3-delta (BCY) powders synthesized using a combustion method are pure perovskite phases. The particles are uniform spherical particles about 50nm. The properties of BCY proton-conducting electrolyte sintered at different temperatures from pressed nanopowders; were systematically investigated. Dense BCY pellets are obtained at temperatures higher than 1400 degrees C for 10 h. Electrical conductivity and resistance to CO2 atmosphere each increase with sintering temperature. Fuel cells having about 0.8 mm thick BCY electrolyte and Pt electrodes co-produce 151 mW cm(-2) electrical power and value-added ethylene with selectivity over 90% at ethane conversion about 35% at 700 degrees C. (C) 2009 Elsevier B.V. All rights reserved.