Hydrogen reduction characteristics of WO3 based on density functional theory

The first principle theory in DFT (Density Function Theory) was applied to study the hydrogen adsorption on O-terminated and WO-terminated surface of WO3 (0 0 1). The exploration of the two terminated surfaces structure and hydrogen adsorption characteristics was conducted from the micro-structure point of view. The result indicates that energy of O-terminated surface with enriched oxygen is higher than the WO-terminated surface with less oxygen. The chemical adsorption occurs when the distance between hydrogen molecules and surface atom ranged from 0.6 angstrom to 0.8 angstrom, while the physical adsorption occurs when the distance was bigger than 0.8 angstrom. The energy of hydrogen adsorption on O-terminated surface is lower than energy of hydrogen adsorption on WO-terminated surface, the chemical adsorption of hydrogen is easier to happen compare to physical adsorption. The energy of hydrogen adsorption on O-1c on O-terminated surface is lower than energy of hydrogen adsorption on O-2c on the same surface. The adsorption of hydrogen not only changes the structure of surfaces of WO3 and cause the conducing electrons jumping into valence band and energy declining but also make a part of electrons in orbit 2p of O to jump into orbit 5p of W.