Atomic S, H and C adsorption on MnO(001) surface and the interaction between H and LaCrO3(001) surface: A computational analysis

Abstract

S poisoning and C deposition are key factors to cause performance degradation of solid oxide fuel cells (SOFC) anodes. The adsorptions of atomic S, H and C on MnO(001) surface and atomic H on LaCrO3(001) surface are systematically investigated using density functional theory (DFT) calculations. The analysis of surface relaxation shows that surface Mn ion slightly moves toward the slab center and surface O ion moves outward on MnO(001) surface. According to the result of adsorption energy, it can be inferred that the MnO weakens the adsorption of atomic S with lower adsorption energies compared to LaCrO3 surface. In addition, the findings show that the preferred site for atomic H adsorption is O site, with the adsorption energy of －1.361 eV, which results in the formation of –OH surface species. Compared to O sites on LaCrO3(001) surface, the atomic H is found to interact weakly with the La and Cr sites. The distances and charges transfer between adsorbate and substrate have also been analyzed. The obtained results are expected to provide some fundamental information for future research on mechanism of S poisoning and C deposition on SOFC anodes.