On the Development of an Electrochemical Sensor to Measure SOFC Fuel Gas Compositions

Abstract

SOFC fuel composition sensing is vital for operation control, monitoring and performance diagnosis. Sensors based on potentiometric measurements can yield accurate compositional correlations provided that chemical equilibrium is established on the electrode. For syngas sensing, sensitivity of open circuit potential to H 2 :CO ratio change was less than that of the humidification level variation. For methane systems, OCP sensors studied either failed to reach equilibrium due to inadequate catalytic activity or suffered from carbon deposition. Impedancemetric sensors provided reasonable responses in syngas and methane systems. Rh-impregnated LSCM/GDC sensors showed good catalytic ability and sensitivity toward methane without coking. Careful calibration is required to rule out ambiguity.