Adsorption/dissociation process of H2S on different FeS2(100) surfaces

Interactions between H2S and an FeS2(1 0 0) 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(1 0 0) 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(1 0 0) was stronger and dissociated spontaneously. Pre-adsorbed oxygen atoms significantly promoted the H2S adsorption/dissociation process. Owing to the E-TS1(H) of H atoms and interaction energy between H and SH, the dissociated E-a on the pre-adsorbed surface decreased. Hydrogen atoms are prone to overflowing of H(2 )molecules on the perfect surface of FeS2(1 0 0), 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(1 0 0) surfaces, providing guidance for developing corrosion protection, hydrogen barrier materials, and catalytic systems.