First-Principles Calculation and Multi-Scale Observation for a Carbon Deposition on a SOFC Anode Near the Interface

Abstract

Carbon deposition site in the Ni/YSZ was studied through microscale observation and first-principles calculation. Early stage of carbon deposition was appropriate reaction to determine the active site because the carbon worked as a visible marker. SEM observation showed that the carbon deposition was progressed not in the overall Ni surface but in the specific sites such as the Ni/YSZ interfaces at low temperature. STEM-HAADF showed that the graphite layer was not found on the Ni(111) surface but on the Ni(112) surface, indicating that the unsaturated step facets such as Ni(112) enhanced the carbon deposition. Similar trends were found in the first-principles calculation. The CH adsorption energy in the Ni(112) facet was higher than that in the Ni(111) facet. In addition, it was suggested that the YSZ structure also influenced the carbon deposition as well as the Ni facet.