Adsorption performance of M-doped (M = Ti and Cr) gallium nitride nanosheets towards SO2 and NO2: a DFT-D calculation

The structure, adsorption characteristics, electronic properties, and charge transfer of SO2 and NO2 molecules on metal-doped gallium nitride nanosheets (M-GaNNSs; M = Ti and Cr) were scrutinized at the Grimme-corrected PBE/double numerical plus polarization (DNP) level of theory. Two types, MGa-GaNNSs and MN-GaNNSs, of doped nanostructures were found. The MGa sites are more stable than the MN sites. The results showed that adsorption of SO2 and NO2 molecules on TiGa,N-GaNNSs is energetically more favorable than the corresponding CrGa,N-GaNNSs. The stability order of complexes is energetically predicted to be as NO2-TiGa-GaNNS > NO2-TiN-GaNNS > SO2-TiGa-GaNNS > NO2-CrN-GaNNS > SO2-TiN-GaNNS > NO2-CrGa-GaNNS > SO2-CrN-GaNNS > SO2-CrGa-GaNNS. The electron population analysis shows that charge is transferred from MGa,N-GaNNSs to the adsorbed gases. The TiGa-GaNNS is more sensitive than the other doped nanostructures to NO2 and SO2 gases. It is estimated that the sensitivity of TiGa-GaNNS to NO2 gas is more than to SO2 gas.