Chemical Adsorption of HF, HCl, and H2O onto YF3 and Isostructural HoF3 Surfaces by First Principles

The two elements, yttrium and holmium, form a geochemical twin pair as their cations possess equivalent ratios of charge to radius. However, despite equal electrostatics, subtle difference in fluoride or chloride affinity is known within solutions. In this work, we investigated whether gap also present the solid phase how it depends on surface configuration. We modeled adsorptions onto β-YF3 (waimirite) isostructural β-HoF3 by periodic density functional theory. To draw conclusions toward vs. water, adsorbates HF, HCl, H2O any four highly abundant surfaces (010), (100), (011), (101) were studied. Among others, conformational landscape was explored 200 ps ab initio molecular dynamics. For stoichiometric both MF3, indeed found stronger for HF than HCl. All (hkl)·H2O showed slightly adsorption energies HoF3, while metal preferences varied surface. While (100) strongest preference preferred YF3 same magnitude.