Mechanisms of methane decomposition and carbon species oxidation on the Pr0.42Sr0.6Co0.2Fe0.7Nb0.1O3−σ electrode with high catalytic activity

Abstract

Carbon deposition on Pr_0.42Sr_0.6Co_0.2Fe_0.7Nb_0.1O_3−σ (PSCFN) and Ni–yttria stabilized zirconia (Ni–YSZ) due to thermal CH₄ decomposition under dry CH₄ has been investigated by using temperature-programmed reaction techniques. The morphologies of carbon formed are characterized by using scanning electron microscopy (SEM). It is found that carbon nanofibers are obviously formed on PSCFN while spherical carbons are formed on Ni–YSZ. Analyses of the results on CH₄ temperature-programmed decomposition and O₂ temperature-programmed oxidation reveal that the high catalytic activity for the cracking of CH₄ and the easier oxidation of the generated carbon species on PSCFN could be the main reason why PSCFN shows high performance and good stability in direct CH₄ fuel solid oxide fuel cells (SOFCs).