Adsorption of sulfur-containing species on LaCrO₃ (001) surface: A first-principles study

Density functional theory calculations are employed to investigate the adsorption of sulfur-containing species on the (001) surface of LaCrO ₃ (LCrO). Molecular adsorption is found to be stable with H ₂S binding preferentially at O site on the LaO-terminated surface. The adsorption of H₂S molecule leads to the electrons transferring from the substrate to the molecule and the charges rearrangement within the molecule. In addition, the adsorption of the corresponding S-containing dissociated species (SH and S) is investigated. SH and S are found to be preferentially bind at the Cr site. We further predict the adsorption energies of sulfur-containing species increase following the sequence H ₂S<SH<S for all the adsorption sites on LCrO (001) surface. Based on the adsorption energy comparison, LCrO is more sulfur-tolerant than traditional Ni-based anode materials, which is qualitatively in line with available experimental results. This study provides a scientific basis for rational design of sulfur-tolerant anode materials for SOFCs.