Single-Atom Adsorption on h-BN along the Periodic Table of Elements: From Pristine Surface to Vacancy-Engineered Sites

The adsorption of single atoms on pristine and defected hexagonal boron nitride (h-BN) was systematically investigated using density functional theory. Elements from the first three rows of the periodic table, together with selected transition and coinage metals, were examined on the pristine surface and at boron- and nitrogen-vacancy sites. On pristine h-BN, adsorption is generally weak and dominated by dispersion forces, with measurable chemisorption limited to highly electronegative atoms such as C, O, and F. The introduction of vacancies transforms h-BN into a chemically active material, increasing adsorption energies by one to two orders of magnitude. The boron vacancy strongly stabilizes metallic and electropositive species through coordination to undercoordinated nitrogen atoms, whereas the nitrogen vacancy selectively binds electronegative and covalent adsorbates. Scaling of adsorption energies with elemental cohesive energies distinguishes regimes of physisorption, chemisorption, and substitutional stabilization. These insights provide a unified description of adsorption trends across the periodic table and establish defect engineering as an effective strategy for tailoring the catalytic, sensing, and electronic properties of h-BN.