Single transition-metal atom doping enhances NO2 adsorption on 1T-PtSe2 monolayer

The structural and electronic properties of monolayer 1T-PtSe₂ doped with various single transition metal (TM) atoms (Co, Ni, Cu, Mo, Rh, Pd, Ir, and Au) at selenium vacancy sites, along with their interaction with NO₂ gas molecules, have been systematically investigated using density functional theory (DFT). TM doping notably enhances the chemical reactivity and alters the electronic structure of PtSe₂, as reflected in stronger NO₂ adsorption, increased charge transfer, and the emergence of impurity states near the Fermi level. These effects are primarily attributed to the introduction of TM nd-orbitals, which facilitate molecular activation. Among the doped systems, Pd-PtSe₂ demonstrates superior gas sensing performance with a short recovery time in the 400–500 K range. These findings provide valuable theoretical guidance for designing high-efficiency gas sensors based on TM-doped PtSe₂ monolayers.