A solid oxide fuel cell (SOFC) unit is constructed with Ni-yttria-stabilized zirconia (YSZ) as the anode, YSZ as the electrolyte, and La0.8Sr0.2MnO3-Ce0.9Gd0.1O1.95 as the cathode. DeNO(x) tests are performed at 700 to 800 degrees C. NO decomposition occurs over the cathode. The N-2 and O-2 produced as the cathode gases can be in molar balance with the decomposed NO. Increasing NOx concentration, adding NO2, and increasing O-2 concentration can all increase the NO conversion; increasing NO conversion with increasing O-2 concentration is beneficial for DeNO(x) of lean-burn exhausts. The amount of oxygen desorbed as the cathode gas (O-2, gas) is much larger than that utilized for power generation; this is an effect of desorption enhancement; this effect can be utilized for SOFC-DeNO(x) with least or no consumption of the anode fuel. The O-2, gas formation rate increases with increasing voltage and is larger at 700 degrees C than at 750 degrees C. With increasing voltage, the NO conversion at 700 degrees C increases but those at 750 and 800 degrees C decrease. When the NO conversion is the same, the consumption of the anode fuel is much less at 700 degrees C than at 750 degrees C. Higher operating voltage results in less fuel consumption. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.044112jes]