The relation between geometry and nickel reactivity was explored using density functional theory. The reactivity was gauged by hydrogen and methane dissociations on atomic nickel and the tetrahedral clusters where binding energies and dissociation barriers were calculated. The results were then compared to Ni 13 icosahedral clusters and (1 1 1) crystal surfaces.
Solid oxide fuel cells (SOFCs) are highly efficient devices for energy conversion. However, their performance is hindered by the poisoning of their oxygen electrode materials by chromium and sulfur species. While previous studies have proposed a nucleation theory of Cr and S poisoning as a mechanism, little is known about the adsorption behaviors and compound formation steps during the poisoning process. This knowledge is critical for understanding the poisoning mechanisms and developing effective mitigation strategies. In this study, the state-of-the-art SOFC oxygen electrode material, La0.6Sr0.4Co0.2Fe0.8O3 (LSCF), is used as a modeling system. A realistic surface structure will be constructed by grand canonical Monte Carlo (GCMC) simulation. Then, the adsorption energies as a function of surface chemistry will be calculated using density functional theory (DFT). The results revealed the importance of surface chemistry in determining the energetics and kinetics of precursor adsorption and compound formation.
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