Sn-Cd modified Ti2CO2 MXene for enhanced harmful gas adsorption: A DFT study

In this study, we investigate the adsorption characteristics of the Ti2CO2 monolayer using density functional theory for harmful gases (NH3, H2S, CH4, NO2, SO2). The optimal adsorption structures of the Ti2CO2 monolayer for different gases are determined, and the adsorption mechanisms are analyzed. NH3 exhibits the highest absolute adsorption energy (0.429 eV) among the gases (NH3, H2S, CH4, NO2, SO2) when physisorbed on the Ti2CO2 monolayer. Substitutional doping of the Ti2CO2 monolayer with the metal element Sn and the transition metal element Cd results in alterations to the material's electronic properties. The adsorption capacities for NH3, H2S, CH4, NO2, and SO2 are significantly enhanced, making the Ti2CO2 monolayer a promising candidate for the adsorption of toxic and hazardous gases. Notably, the doping process significantly improves the adsorption performance of Ti2CO2 monolayer for NO2, with the adsorption energy increasing by a factor of 10.35 compared to the original material. This substantial enhancement provides a new approach for doping modifications of Ti2CO2 monolayers to facilitate the adsorption of various gases.