Exploring the adsorption of CO toxic gas on pristine and M-doped (M = Ti, Cr, Fe, Ni and Zn) GaN nanosheets

The capability of pristine and M-doped (M = Ti, Cr, Fe, Ni and Zn) gallium nitride nanosheets (M-GaNNS) was explored at the Grimme-corrected PBE/double numerical plus polarization (DNP) level of theory for adsorbing and sensing of the carbon monoxide (CO) molecule. It was found that the binding energies for MGaGaNNS were greater than for MNGaNNS, indicating that Ga sites are more energetically favorable than N sites for M doping. The results demonstrated that the decrease of the energy gap for Fe-Ga,Fe-N-GaNNS and Zn-Ga-GaNNS was greater than the others. Besides, M doping of GaNNS increased the adsorption energies of CO toxic gas in comparison with pristine GaNNS. The energies of adsorption were calculated to be in the range of -0.03 (Ti-Ga-GaNNS) to -2.55 (Fe-N-GaNNS) eV. In addition, adsorption of CO gas decreased the energy gap of the GaNNS and the order was E-g (MNGaNNS) > E-g (MGaGaNNS). Due to the changes in the energy gaps of the GaNNS upon adsorption of CO, it was predicted that CrGaGaNNS and FeNGaNNS could be suitable for sensing of CO gas. Based on the obtained results, it is predicted that FeNGaNNS could be a good candidate for sensing and removing the toxic air pollutant CO gas.