The effects of solid carbon on NO electrocatalytic reduction in the presence of O-2 content, as low as can be found in a gasoline engine, were investigated. Tubular solid-state fuel cells filled with Fe-loaded carbon materials (Fe-loaded activated carbon, Fe-AC, and Fe-loaded carbon black, Fe-BC) were fabricated for electrochemical reduction in the configuration of LSM as the cathode, NiO-YSZ mixed powder as the anode, and YSZ as the electrolyte. A moderate NO removal efficiency of 60% and maximum peak power density of 0.035 W cm(2) were achieved for Fe-AC in the presence of 1% O-2, whereas no such performances were detected in the case of AC. Following TGA-MS and in-situ analyses of exit gases from the anodes, it can be concluded that Fe-loaded carbon materials promote CO formation in Boudouard reactions by utilizing excess oxygen transported from the cathode, which is capable of alleviating the impact of oxygen on NO removal while also enhancing electrical performance. The formation of CO contributes to the reduction of both concentration polarization loss and activation polarization loss at both electrodes. (C) 2020 Elsevier Inc. All rights reserved.