Ab initioinvestigation of the role of charge transfer in the adsorption properties ofH2, N2, O2,CO,NO,CO2, NO2, andCH4on the van der Waals layeredSn3O4semiconductor

We report an atomistic investigation, based on density functional theory calculations within the D3 van der Waals correction, of the adsorption properties of ${\mathrm{H}}_{2}, {\mathrm{N}}_{2}, {\mathrm{O}}_{2}, \mathrm{CO}, \mathrm{NO}, {\mathrm{CO}}_{2}, {\mathrm{NO}}_{2}$, and ${\mathrm{CH}}_{4}$ on the semiconductor ${\mathrm{Sn}}_{3}{\mathrm{O}}_{4}(010)$ monolayer surface. Except for ${\mathrm{NO}}_{2}$ and $\mathrm{NO}$ molecules, the adsorption energies are from $\ensuremath{-}64\phantom{\rule{0.16em}{0ex}}\mathrm{m}\mathrm{e}\mathrm{V}$ (${\mathrm{H}}_{2}$) up to $\ensuremath{-}167\phantom{\rule{0.16em}{0ex}}\mathrm{m}\mathrm{e}\mathrm{V}$ (${\mathrm{CO}}_{2}$) with the molecule-surface distances larger than $3.30\phantom{\rule{0.16em}{0ex}}\text{\AA{}}$ for all molecules, and hence, minor effects were observed on the ${\mathrm{Sn}}_{3}{\mathrm{O}}_{4}(010)$ surface electronic structure upon adsorption. ${\mathrm{NO}}_{2}$ has the largest adsorption energy ($\ensuremath{-}525\phantom{\rule{0.16em}{0ex}}\mathrm{m}\mathrm{e}\mathrm{V}$), which can be explained by closer approach of the two $\mathrm{O}$ atoms towards the surface, while $\mathrm{NO}$ binds to the surface with about half of the ${\mathrm{NO}}_{2}$ adsorption energy (e.g., $\ensuremath{-}279\phantom{\rule{0.16em}{0ex}}\mathrm{m}\mathrm{e}\mathrm{V}$). From Bader analysis, we found substantial charge transfer from the surface to the molecules, $\ensuremath{-}0.52\phantom{\rule{0.16em}{0ex}}e$ (${\mathrm{NO}}_{2}$) and $\ensuremath{-}0.23\phantom{\rule{0.16em}{0ex}}e$ ($\mathrm{NO}$), which is consistent with the smaller distances to the surface, 2.46 and $2.82\phantom{\rule{0.16em}{0ex}}\text{\AA{}}$, respectively. Thus, those results suggest an improved detection performance of ${\mathrm{Sn}}_{3}{\mathrm{O}}_{4}$ towards ${\mathrm{NO}}_{2}$, which can help to design sensor devices based on the ${\mathrm{Sn}}_{3}{\mathrm{O}}_{4}(010)$ monolayers.