2018 Volume 126 Issue 10 Pages 794-800
A solid oxide fuel cell with an yttria-stabilized zirconia (YSZ) electrolyte, Ni–YSZ anode and Ru–YSZ cathode was fabricated to measure the cell performance at 500–800°C using a H2, CO or CO–H2O fuel and air oxidant. The terminal voltage drop at a larger current density was due to the overpotential at the electrodes. A part of CO fuel was electrochemically oxidized to produce an electric power and some fractions of CO fuel were decomposed to form CO2 gas and solid carbon (disproportionation reaction, 2CO → CO2 + C). In the CO–H2O fuel, electrochemical oxidation of a CO fuel, CO disproportionation, the water–gas shift reaction (CO + H2O → H2 + CO2) and oxidation of deposited carbon (C + H2O → H2 + CO) proceeded in the anode. It is possible to produce an electric power and a H2 fuel at the same time during the operation of a SOFC using a CO–H2O fuel.