Cr adsorption and diffusion on LSCF surface: a first-principles study

To address the Cr poisoning issue in the cathode of Solid Oxide Fuel Cell, it is essential to investigate the adsorption and diffusion of Cr atoms on the surface of lanthanum strontium cobalt ferrite (LSCF) cathodes to uncover the Cr poisoning mechanism. This work systematically calculates the potential energy surface (PES) for the adsorption of Cr atoms on the La(Sr)O-terminated (1 0 0) surface of LSCF. The possible diffusion paths of Cr atoms are derived from the PES, and the diffusion properties are further examined using the CI-NEB method. The results indicate that the lowest adsorption energy of the Cr atom is −6.760 eV at the Hollow sites. Two Cr diffusion paths across the entire surface in the x and y directions are also identified. The charge transfer among different atoms during the diffusion process is analyzed using Bader charge analysis, and the COHP method is employed to further reveal the bonding characteristic of Cr atoms on the surface. During the diffusion process, Cr atoms dynamically form and break bonds with surface oxygen atoms. This study provides theoretical insights to support subsequent experiments aimed at reducing the Cr poisoning effect on the LSCF surface.