Hydroxylation and fluorination on γ-Al2O3(110) surfaces: First-principles and transition state calculations

Abstract

Abstract In this paper, the adsorption mechanism of HF and H2O on the γ-Al2O3 and hydroxylated surfaces were built and calculated. The calculated results show that the main active adsorption sites are concentrated near the octahedral hole sites. There are two types of chemical adsorption of H2O: ▲Al-O-H2 and ▲Al-O-H*▲Oa-H. The adsorption energy range is -0.30~-1.75eV. With the increase of adsorption energy, H2O gradually inclines to the surface to form OH. The chemisorption form of HF is ▲Al-F and ▲O-H, with the adsorption energy in the range of -0.61 to -2.41eV. At low coverage, there were more active adsorption sites on the surface, and the interaction between OH and HF adsorption was less. At high coverage, the active site occupied by OH tended to be saturated, and HF could not break bonds to form Al-F, so the adsorption effect decreased. When the HF coverage is about 0.4, the binding is the most stable, and the adsorption energy is -2.97eV.