Superior sensing performance of two-dimensional ruthenium carbide (2D-RuC) in detection of NO, NO2 and NH3 gas molecules

In this work, for the first time, we report the enhanced adsorption of nitrogen-containing gas (NCG) molecules such as NO, NO2 and NH3 on two-dimensional ruthenium carbide (2D-RuC). Density functional theory calcu-lations are performed to analyze the electronic properties, charge transfer, work function, recovery time and sensitivity. The computed physisorption energies for NO, NO2 and NH3 molecules are-1.718 eV,-1.480 eV and-0.895 eV respectively. Electronic property analysis reveals that 2D-RuC exhibits metallic character in the presence of adsorbed molecules, which is suitable for a good sensing performance. From the Bader charge analysis, we found that significant amount of charge is transferred from NO (0.210 e) and NO2 (0.413 e) mol-ecules to the 2D-RuC sheet; whereas, charge transfer from the surface to the NH3 molecule is observed (-0.195 e). We also noticed significant changes in the work function of 2D-RuC after the adsorption of NCGs which indicates the high sensitivity and selectivity of this 2D material. The computed temperature-dependent desorption time of the NH3 molecule from the 2D-RuC sheet is much shorter (in the order of seconds) than other molecules. The results indicate that 2D-RuC is an excellent material for the design of reusable NH3 sensor devices.