Adsorption of gases on doped graphene quantum dots with (TM = Ni, Pd, and Pt): DFT and TD-DFT investigation

The effects of TM (Ni, Pd, and Pt) doping and the adsorption of NO, NO2, and NH3 gases on the electrical as well as optical properties of the armchair-hexagonal (AHEX) graphene quantum dots have been investigated using DFT and TD-DFT calculations at the B3lyp/SDD level of the theory. TM-doped AHEX GQD enhances the adsorption energies for NO, NO2, and NH3 gases. Adsorption of NO, NO2, and NH3 gases changes the Eg of Ni-AHEX (−36.55 %, −45.14 %, 13.49 %), Pd-AHEX (−42.76 %, −87.04 %, 8.48 %), and Pt-AHEX (−37.05 %, −35.91 %, 15.83 %), respectively. In addition, ΔG was negative for all configurations indicating that gas molecule adsorption on TM-doped AHEX GQD is always thermodynamically advantageous. According to the UV–Vis examination, the adsorption of NO, NO2, and NH3 gases changes the material from UV-active to visible-active. In conclusion, TM-doped AHEX GQD is a viable candidate material for application as a sensor of harmful NO, NO2, and NH3 gases.