Quantum Mechanical Study of Clean and H-Covered α-MoO3(100) Surface

Abstract

Structure and electronic properties of the α-MoO3(100) surface, as well as H adsorption on the α-MoO3(100) surface have been studied with periodic slab Hartree–Fock calculations. Gradient corrected density functional calculations have been performed in this study. The structure and electronic properties of the (100) surface are in agreement with experimental and previous theoretical results. Local electronic structure near the different surface oxygen sites are analyzed with Mulliken Population Analysis. The oxide is partially ionic and the symmetrically oxygens exhibit more ionic feature while the terminal oxygens are more covalent. Electrostatic potentials show broad negative minima above the terminal oxygen centers, which suggest that electrophilic adparticles, like H, resulting from surface reactions, will be attracted preferentially at these sites. The results of the H adsorption on the (100) surface are interpreted based on charge-transfer interactions between the surface and H species. It is found that terminal oxygen sites are the most stable binding site. Ionic relaxation of the α-MoO3(100) surface for the adsorption of hydrogen has no effect on the chemical properties and hydrogen atoms adsorbed favorably on the α-MoO3(100) surface at full coverage.