Hydrogen Trapping in Carbon-Doped $h$-BN/Rh(111) Nanomesh

Atomic or molecular preferential adsorption on surface nanotemplates provides a facile and feasible means of fabricating ordered low-dimensional nanostructures with tailored functionality. In this study, by employing density-functional theory calculations, we demonstrate (1) the carbon doping of the (B,N)$=$(fcc$_{\mathrm{Rh}}$,top$_{\mathrm{Rh}}) h$-BN/Rh(111) nanomesh, and (2) the selective trapping of hydrogen atoms on these dopants at various sites of the nanomesh -- within the pore, on the wire, and at an intermediate site. Contrary to carbon-doped boron nitride sheets, it is energetically more favorable for a carbon impurity to replace a nitrogen atom as compared to a boron atom at all three sites of the nanomesh. In addition, the adsorption energy of hydrogen adsorbates is greater at the wire of a nitrogen-substituted nanomesh relative to that in its pore, while this adsorption energy is invariant at different sites in a boron-substituted nanomesh.