The characteristics of defective ZrS2 monolayers adsorbed various gases on S-vacancies: A first-principles study

The characteristics of defective ZrS2 monolayers containing S-vacancies adsorbed various gases (NO, NO2, CO, SO2, N-2, H-2, O-2, CO2) were studied using a theoretical approach based on the density functional theory calculations. A favorable configuration for each gas adsorption was also found. The structural properties of defected ZrS2 monolayers with S-vacancies adsorbed the given gas contents were elucidated. The obtained results show that the defected ZrS2 monolayers with S-vacancies enhance the capacity of the gas adsorption in respect of the perfect ZrS2 structures. Among those gases, the CO2, CO and N-2 molecules are physically adsorbed on S-vacancies of the defected ZrS2 monolayers, whilst the O-2, NO, SO2 molecules are chemically adsorbed in the areas closed to S-vacancies of the ZrS2 monolayers. Moreover, a NO2 molecule can be separated by a S-vacancy of the defected ZrS2 monolayer. The results of this work suggest that defective ZrS2 monolayers with S-vacancies can be used as an adsorbent using in gas sensors to detect CO2, CO and N-2 gas contents. Therein, the highest sensitivity in detecting N-2 molecules is observed.