Sn₃C₂monolayer with transition metal adatom for gas sensing: a density functional theory studies

The gas sensing properties of pristine Sn₃C₂monolayer and different transition metal adatom (TM-Sn₃C₂, where TM = Fe, Co, Ni, Cu, Ru, Rh, Pd and Ag) was investigated using van der Waals corrected density functional theory. The understanding and potential of use of Sn₃C₂monolayers as sensors or adsorbent for CO, CO₂, NO, NO₂and SO₂gaseous molecules is evaluated by calculating the adsorption and desorption energetics. From the calculated adsorption energies, we found that the pristine Sn₃C₂monolayer and 3dTM has desirable properties for removal of the considered molecules based on their high adsorption energy, however the 4dTM is applicable as recoverable sensors. We applied an Arrhenius-type equation to evaluate the recovery time for the desorption of the molecules on the pristine and TM adatom on Sn₃C₂monolayer. We found that the negative adsorption energies from -1 to -2 eV of the molecules resulted in easier recovery of the adsorbed gases at reasonable temperatures compared to adsorption energies in between 0 and -1 eV (weakly physiosorbed) and below -2 eV (strongly chemisorbed). Hence, we obtained that the Rh-Sn₃C₂, Ru-Sn₃C₂, Pd-Sn₃C₂, Pd-Sn₃C₂, and Rh-Sn₃C₂monolayers are good recoverable scavengers for the CO, CO₂, NO, NO₂, and SO₂molecules. The current theoretical calculations provide new insight on the effect of TM adatoms on the structural, electronic, and magnetic properties of the Sn₃C₂monolayer and different transition metal adatom as well as shed light on their application as gas sensors/scavengers.