Interaction study of CO and NO pollutant gases with pristine, defected and doped -CX (X=N, P) monolayers using density functional theory

CO and NO are two of the most pollutant gases that exist in the environment, which makes their tracing highly crucial. In this problem, we have investigated the adsorption performances of highly toxic CO and NO gases over pristine, defect-tuned, and Aluminium (Al)-doped alpha-CX (X=N, P) monolayers. In addition to the adsorption properties, we have calculated electronic properties such as band structure, projected density of states (PDOS) and charge transfer, sensing properties such as work function and recovery time for pristine, defect-tuned, and Al-doped alpha-CX before and after the gas adsorption process. Given the poor adsorption energies and large adsorption distances, pristine alpha-CX monolayers are not suitable candidates for the toxic gas sensors. In case of functionalized alpha-CX, the adsorption energy is highest in case of C-defected alpha-CN for CO gas adsorption. For interaction of NO gas molecule with functionalized alpha-CX, Al-doped alpha-CN is deemed to be best candidate for adsorption. The computed recovery times are extremely long (exceeding several hours) in the best-case scenarios, this implies that C-defected alpha-CN and Al-doped alpha-CN are most suitable for CO and NO gas removal applications.