Al-doped hexa-peri-hexabenzocoronene nanographene as an electronic CO gas sensor

Based on the experimental reports, Al-doping significantly increases the carbonaceous nanostructure sensitivity toward CO gas. Here, using B3LYP-gCP-D3 method, the Al-doping effect on the sensing properties of the hexaperi-hexabenzocoronene (HBC) nanographene to CO gas is studied. The sensing response (S) was correlated to the HOMO-LUMO gap (E-g) of adsorbent, indicating a good agreement with the experiment. The pristine HBC physically adsorbs the CO gas with adsorption energy of -2.3 kcal/mol, causing no impact on its E-g and conductivity. The predicted S of HBC toward CO is 1.09, increased to 134.65 by the Al-doping. The Al atom catalyzes the reaction O-2 + 2CO -> 2CO(2), passing through an energy barrier of 10.7 kcal/mol. This reaction in the origin of the conductivity changes because of the electron donation and back-donation process between the reactants and the surface. Finally, a short recovery time of 15.7 mu s is predicted for Al-doped HBC-based sensor.