The investigation of the influence of the addition of cerium dioxide to the anode composition on the internal carbon dioxide conversion of methane on second-generation SOFCs

The effect of the addition of cerium dioxide in different forms – GDC (gadolinia-doped ceria, CeO2 doped with 10 mol% Gd2O3) layer on the surface, CeO2 nanoparticles – on the results of internal carbon dioxide conversion of methane at the anode of solid oxide fuel cells was studied in the present work. The studies were carried out mainly using a technique that combined electrochemical techniques, Raman spectroscopy, and flow gas analysis. It was shown that the long-term operation of the fuel cell under conditions of carbon dioxide conversion led to the formation of carbon deposits throughout the thickness of the model samples. The presence of carbon was confirmed by the micrographs of a scanning electron microscope, as well as the results of energy-dispersive analysis and Raman spectroscopy. It was found that carbon had a form of graphite inside the fuel electrode. Polymerization of carbon clusters into carbon nanotubes was observed closer to the free surface of the anode. Raman spectroscopy studies showed the presence of D- and G-graphite bands in the spectrum, which also indicated the presence of disordered and filamentary carbon. At the same time, longer exposure to carbon-containing fuel led to an increase in the proportion of carbon polymerized into nanotubes. Cerium dioxide was shown to have a positive effect on the electrochemical characteristics of the cells: the time of stable operation increased, and the amount of carbon deposits decreased even after adding a small amount of CeO2.