In situ Raman spectroscopic analysis of the coking resistance mechanism on SrZr0.95Y0.05O3−x surface for solid oxide fuel cell anodes

While the coking resistance of Ni/yttria-stabilized zirconia (YSZ) anodes in solid oxide fuel cells (SOFCs) toward hydrocarbon fuel can be improved by adding SrZr0.95Y0.05O3−x (SZY) as a proton conductor, the exact mechanism is still unclear. In this study, the surface chemistry of SZY is investigated using in situ Raman spectroscopy to clarify the coking resistance mechanism. Upon exposure to dry propane at 500 °C, the intensity of the Raman peaks corresponding to CO3 species decreases with time, suggesting that the surface-located CO3 groups are consumed through a reaction with deposited carbon or dry reforming of propane, which reduces the tendency of coking. These consumed CO3 groups can then be regenerated through a reaction between water vapor and deposited carbon. The presence of adsorbed water on SZY, which facilitates a carbon removal reaction and the steam reforming of propane, is confirmed by thermogravimetric analysis (TGA). The reactivity of the CO3 groups and the adsorbed water on SZY thus contribute to removing deposited carbon, resulting in the improved coking resistance of Ni/YSZ-SZY anode. [Display omitted] •Coking resistance mechanism of SrZr0.95Y0.05O3−x (SZY) was studied for SOFC anode.•Dynamics of adsorbates on SZY surface was investigated by in situ Raman spectroscopy.•Interaction between carbon and CO3 on SZY was observed in C3H8 and wet atmosphere.•–CO3 group and adsorbed H2O on SZY surface contribute to carbon removal reaction.