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, M_Ga-GaNNSs and M_N-GaNNSs, of doped nanostructures were found. The M_Ga sites are more stable than the M_N sites. The results showed that adsorption of SO₂ and NO₂ molecules on Ti_Ga,N-GaNNSs is energetically more favorable than the corresponding Cr_Ga,N-GaNNSs. The stability order of complexes is energetically predicted to be as NO₂-Ti_Ga-GaNNS > NO₂-Ti_N-GaNNS > SO₂-Ti_Ga-GaNNS > NO₂-Cr_N-GaNNS > SO₂-Ti_N-GaNNS > NO₂-Cr_Ga-GaNNS > SO₂-Cr_N-GaNNS > SO₂-Cr_Ga-GaNNS. The electron population analysis shows that charge is transferred from M_Ga,N-GaNNSs to the adsorbed gases. The Ti_Ga-GaNNS is more sensitive than the other doped nanostructures to NO₂ and SO₂ gases. It is estimated that the sensitivity of Ti_Ga-GaNNS to NO₂ gas is more than to SO₂ gas.