Effect of metal (Zn and Co) doped/co-doped on Ti3C2O2 MXene to NO gas sensing capability: A DFT study

The gas-sensitivity of ammonia, nitric oxide, nitrogen dioxide, methane, and formaldehyde on pristine Ti3C2O2 and transition metal-doped Ti3C2O2 were studied systematically by density functional theory (DFT). The electron density and density of states of the adsorption systems were further analyzed to study the sensing performance. The obtained results reveal that doping with transition metals (TM = Co, Zn) to pristine Ti3C2O2 could significantly enhance the adsorption abilities of Ti3C2O2, leading to a stronger interaction between gas molecules and Ti3C2O2. Among all systems, the adsorption of NO molecule by Zn–Co co-doped Ti3C2O2 is significantly improved. The results of the density of states and charge density difference certify the charge of the surface charge distribution of Zn and Co modified Ti3C2O2. Calculated electronic properties for studied systems indicate that Zn–Co co-doped Ti3C2O2 presents high sensitivity to NO molecules. The results showed that Zn–Co co-doped Ti3C2O2 MXene is an excellent material for NO sensors.