  Oxide materials offer a wide range of interesting physical and chemical
properties. Even more versatile behavior of oxides is seen at the nanoscale,
qualifying these materials for a number of applications. In this study we used
DFT calculations to investigate the physical and chemical properties of small
hexagonal MgO nanotubes of different length. We analyzed the effect of Li, B,
C, N, and F doping on the properties of the nanotubes. We find that all dopants
favor the edge positions when, incorporated into the nanotubes. Doping results
in the net magnetization whose value depends on the type of the impurity. Using
the CO molecule as a probe, we studied the adsorption properties of pristine
and doped MgO nanotubes. Our results show that the dopant sites are also the
centers of significantly altered chemical reactivity. While pristine MgO
nanotubes adsorb CO weakly, very strong adsorption at the dopant sites (B-, C-,
and N-doped nanotubes) or neighboring edge atoms (F- and Li-doped nanotubes) is
observed. Our results suggest that impurity engineering in oxide materials can
be a promising strategy for the development of novel materials with possible
use as selective adsorbents or catalysts.
