Detection of Carbon, Sulfur, and Nitrogen Dioxide Pollutants with a 2D CaO Nanostructured Material.

In recent times, nanomaterials have been applied for the detection and sensing of toxic gases in the environment owing to their large surface-to-volume ratio and efficiency. CO is a toxic gas that is associated with causing global warming, while SO and NO are also characterized as nonbenign gases in the sense that when inhaled, they increase the rate of respiratory infections. Therefore, there is an explicit reason to develop efficient nanosensors for monitoring and sensing of these gases in the environment. Herein, we performed quantum chemical simulation on a CaO nanocage as an efficient nanosensor for sensing and monitoring of these gases (CO, SO, NO) by employing high-level density functional theory modeling at the B3LYP-GD3(BJ)/6-311+G(d,p) level of theory. The results obtained from our studies revealed that the adsorption of CO and SO on the CaO nanocage with adsorption energies of -2.01 and -5.85 eV, respectively, is chemisorption in nature, while that of NO possessing an adsorption energy of -0.69 eV is related to physisorption. Moreover, frontier molecular orbital (FMO), global reactivity descriptors, and noncovalent interaction (NCI) analysis revealed that the adsorption of CO and SO on the CaO nanocage is stable adsorption, while that of NO is unstable adsorption. Thus, we can infer that the CaO nanocage is more efficient as a nanosensor in sensing CO and SO gases than in sensing NO gas.