Redox-Induced Self-Modification of Cermet Anodes of Ni-CeO2-Based Oxide for Solid Oxide Fuel Cells

Recently, the strong chemical interaction between Ni and GDC (Gd2O3−CeO2) was reported for the cermet anode of Ni−GDC in solid oxide fuel cells (SOFCs);1 CeO2 species migrated on the Ni surface after exposure to the reducing atmosphere. This surface modification of nickel affected the catalytic properties for carbon deposition and CO adsorption. Generally, such a chemical interaction is promoted by the oxidation-reduction (redox) treatment. In this study, then, the influence of redox treatment on catalytic and electrochemical properties of Ni-GDC cermets was investigated in detail to establish a new design concept of anodes. The Ni−GDC cermet subjected to the redox treatment showed high tolerance to carbon deposition. Furthermore, the redox treatment did not affect the mechanism of electrochemical hydrogen oxidation in humidified hydrogen atmospheres. We also demonstrated the stable power generation of the single cell employing the optimized Ni−GDC anode at 1000°C in a wet methane atmosphere with a steam to carbon ratio of 0.1.