Adsorption/dissociation process of H2S on different FeS2(1 0 0) surfaces

Abstract

Interactions between H2S and an FeS2(100) surface significantly affect the corrosion of carbon steel, and effects of pre-adsorbed atoms on the H2S adsorption/dissociation process remain unclear. Herein, we adopted the Hubbard U-corrected GGA + U method of density functional theory and considered the effect of spin polarization. The stability order of different FeS2 low-dimensional surfaces was calculated. The adsorption/dissociation mechanism of H2S on perfect and pre-adsorbed FeS2(100) surfaces was explored, and the theoretical basis of the improved hydrogen barrier effect in FeS2 was revealed. The stability order of different FeS2 low-dimensional surfaces was (100) > (110) > (111). The adsorption capacity of H2S on the surface of the pre-adsorbed FeS2(100) was stronger and dissociated spontaneously. Pre-adsorbed oxygen atoms significantly promoted the H2S adsorption/dissociation process. Owing to the ETS1H of H atoms and interaction energy between H and SH, the dissociated Ea on the pre-adsorbed surface decreased. Hydrogen atoms are prone to overflowing of H2 molecules on the perfect surface of FeS2(100), and FeS2 had better hydrogen barrier properties. This study enhances our understanding of structural properties of FeS2 and the interaction of H2S with different FeS2(100) surfaces, providing guidance for developing corrosion protection, hydrogen barrier materials, and catalytic systems.