Adsorption of small molecules on a Pmma CO monolayer

The uptake of pollutant gases from the environment is an important topic in nanomaterial science. Although this issue has been extensively studied from all aspects, there is still a need for efficient adsorbent substrates. As carbon-based materials are reliable for removal of gas molecules, we studied the capacity of the recently predicted monolayer of Pmma CO for detection of gas molecules, especially for uptake of H₂S. Monolayer Pmma CO was found to be a stable material with unexpected physical and chemical properties. Motivated by this, on the basis of the first-principles plane-wave method in density functional theory, using the generalized gradient approximation, we chose pristine monolayer Pmma CO and two different defective Pmma CO structures as substrates and investigated the adsorption behavior of the H₂S molecule on these monolayers. Moreover, we calculated the binding energies of other gas molecules, such as CO, CO₂, NO, and NO ₂, on pristine monolayer Pmma CO. We also examined the properties of the point-defect structures of monolayer Pmma CO in detail. As the calculated binding energies of H₂S on the chosen substrates are moderate, we investigated the adsorption of H₂S on Ni-doped Pmma CO. We found that the binding energy for the toxic gas H₂S greatly increases on the Ni-doped Pmma CO structure. Our results show that monolayer Pmma CO can be modified by point defects, specifically by atom doping. Thus, the Ni-doped Pmma CO substrate could be an alternative medium for detection of H₂S.