A stack of solid oxide fuel cells (SOFCs) can be used as an automotive catalytic converter for lean-burn NO emission control. With a simulated SOFC stack, it is demonstrated that this converter can reduce NO in the lean-burn engine exhaust to zero no matter how large the inlet NOx concentration is. An SOFC unit operating at 600 C was constructed with Ni-YSZ as the anode, YSZ as the electrolyte, and Cu-added La0.3Sr0.2MnO3-Ce0.9Gd0.1O1.95 as the cathode. The NOx conversion increases not only with decreasing NO concentration in the low NO concentration range but also with increasing NO concentration in the high NO concentration range. In addition, the NO conversion increases with increasing O-2 concentration and can increase with adding SO2. Simultaneous control of CO emission via oxidation can be performed in this converter. (C) 2011 Elsevier B.V. All rights reserved.