The enhanced adsorption mechanism of ethanol on (Fe-Zn) bimetallic-doped Ti2CO2 monolayers: a DFT study

Ti2C as a new two-dimensional layered MXene material has a certain potential in the sensor field. The adsorption properties of gases (NH3, NO, ethanol, CO) on intrinsic Ti2CO2 and transition metal atoms (Fe, Zn) doped Ti2CO2 were studied by density functional theory systematically. The geometric structure, adsorption energy, molecular dynamics, energy band structure, density of states, charge transfer, and differential charge density of these molecules at five sites of intrinsic Ti2CO2, Fe-doped Ti2CO2, Zn-doped Ti2CO2, FeZn-adjacent co-doped Ti2CO2 and FeZn-pair co-doped Ti2CO2 were analyzed. The results show that the activity of the substrate can be improved by the introduction of Fe-Zn transition metals. The high adsorption energy of ethanol gas at (A) FeZn site is -1.98eV with the short adsorption distance. The high charge transfer between the metal co-doped Ti2CO2 substrate and ethanol gas was also found. The results suggest that the Fe-Zn bimetallic-doped Ti2CO2 monolayer may be a potential sensing material for the detection of ethanol gas.