H2S Dissociation on Defective or Strained Fe (110) and Subsequent Formation of Iron Sulfides: A Density Functional Theory Study

Abstract

In this paper, spin-polarized periodic density functional theory-based simulations were performed to investigate H2S adsorption and dissociation on the defective and strained Fe (110) surfaces which exist in real oil exploitation and transport. It was found that the defective surface facilitates H2S adsorption and dissociation with respect to the perfect surface, while the homogeneous external stresses, giving rise to uniform lattice expansion, show negligible effects for the strain estimated from experiment. More interestingly, the simulations predicted a correct order of phase transition at the Fe (110) surface by using the chemical potential based thermodynamic model, that is, from the elementary Fe crystal to the FeS crystal to the FeS2 crystal to the elementary S crystal with the S coverage on the Fe (110) surface increasing.