Electrocatalytic performance and carbon tolerance of ternary Au-Mo-Ni/GDC SOFC anodes under CH4-rich Internal Steam Reforming conditions

• Published in: Catalysis today 2018-07, Vol.310, p.157-165
• Main Authors: Neofytidis, Ch, Dracopoulos, V., Neophytides, S.G., Niakolas, D.K.
• Format: Article
• Language: English
• Subjects: Au-Mo-Ni/GDC electrocatalyst; Carbon formation; CH4-rich Internal Steam Reforming; SOFCs
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2017.06.028

[Display omitted] •Au-Mo modification enhances the intrinsic properties of Ni/GDC as an electrode.•3Au-3Mo-Ni/GDC is a moderate catalyst, but a better and more stable electrocatalyst.•The ternary electrode is less prone to C formation.•C formation affected the Rpol of the Ni/GDC anode and resulted in degradation.•The cell with Au-Mo-Ni/GDC degraded due to Ni re-oxidation, which affected the Rohm. The present work examines the effect of Au-Mo modification on the electrocatalytic performance and carbon tolerance of Ni/GDC for the internal CH4 steam reforming reaction. Comparative electrocatalytic measurements are presented between cells that comprise Ni/GDC and 3Au-3Mo-Ni/GDC as anodes under CH4-rich feed (S/C=0.3), without dilution in a carrier gas. Complementary electrochemical and physicochemical characterization was performed to investigate the possible modifications on the electrochemical and structural properties of the electrodes. In brief, the cell with Ni/GDC was more active catalytically, but exhibited worst electrocatalytic performance and operated for significantly shorter period with a degradation rate 5.5mV/h. The main degradation factor was the higher carbon formation rate, which increased gradually and affected the polarization resistance of the electrode. The cell with 3Au-3Mo-Ni/GDC was moderately active catalytically, but performed better and lasted for the double operating period with a degradation rate 2.6mV/h. In the latter case the carbon formation rate was almost negligible and degradation was attributed to the gradual re-oxidation of nickel, which affected the ohmic resistance of the electrode.