  Chemical functionalization has proven to be a promising means of tailoring
the unique properties of graphene. For example, hydrogenation can yield a
variety of interesting effects, including a metal-insulator transition or the
formation of localized magnetic moments. Meanwhile, graphene grown by chemical
vapor deposition is the most suitable for large-scale production, but the
resulting material tends to be polycrystalline. Up to now there has been
relatively little focus on how chemical functionalization, and hydrogenation in
particular, impacts the properties of polycrystalline graphene. In this work,
we use numerical simulations to study the electrical properties of hydrogenated
polycrystalline graphene. We find a strong correlation between the spatial
distribution of the hydrogen adsorbates and the charge transport properties.
Charge transport is weakly sensitive to hydrogenation when adsorbates are
confined to the grain boundaries, while a uniform distribution of hydrogen
degrades the electronic mobility. This difference stems from the formation of
the hydrogen-induced resonant impurity states, which are inhibited when the
honeycomb symmetry is locally broken by the grain boundaries. These findings
suggest a tunability of electrical transport of polycrystalline graphene
through selective hydrogen functionalization, and also have implications for
hydrogen-induced magnetization and spin lifetime of this material.
