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

Based on density functional theory calculations, this study analyzed the gas-sensing performance of TiCT (T=O, F, OH) monolayers modified with precious metal atoms (Ag and Au) for HCHO and CH gas molecules. Firstly, stable structures of Ag- and Au-single-atom doped TiCT (T=O, F, OH) surfaces were constructed and then HCHO and CH 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 TiCO for HCHO and CH. In comparison, the effect of the Au modification was better than that of Ag. For TiCF, the Ag and Au doping modifications did not significantly change the adsorption effects for HCHO and CH. However, the Ag and Au doping modifications decreased the adsorption of TiC(OH) for HCHO, while there was no significant change in the gas adsorption for CH. The above results serve as a theoretical foundation for the design of new sensors for HCHO and CH.