The Gas-Sensing Properties of Ag-/Au-Modified Ti3C2Tx (T=O, F, OH) Monolayers for HCHO and C6H6 Gases

Based on density functional theory calculations, this study analyzed the gas-sensing performance of Ti3C2Tx (T=O, F, OH) monolayers modified with precious metal atoms (Ag and Au) for HCHO and C6H6 gas molecules. Firstly, stable structures of Ag- and Au-single-atom doped Ti3C2Tx (T=O, F, OH) surfaces were constructed and then HCHO and C6H6 gas molecules were set to approach the modified structures at different initial positions. The most stable adsorption structure was selected for further analysis of the adsorption energy, adsorption distance, charge transfer, charge deformation density, total density of states, and partial density of states. The results show that the Ag and Au modifications improved the adsorption performance of Ti3C2O2 for HCHO and C6H6. In comparison, the effect of the Au modification was better than that of Ag. For Ti3C2F2, the Ag and Au doping modifications did not significantly change the adsorption effects for HCHO and C6H6. However, the Ag and Au doping modifications decreased the adsorption of Ti3C2(OH)2 for HCHO, while there was no significant change in the gas adsorption for C6H6. The above results serve as a theoretical foundation for the design of new sensors for HCHO and C6H6.