Sn3C2 monolayer with transition metal adatom for gas sensing: a density functional theory studies

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The gas sensing properties of pristine Sn3C2 monolayer 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 Sn3C2 monolayers as sensors or adsorbent for CO, CO2, NO, NO2 and SO2 gaseous molecules is evaluated by calculating the adsorption and desorption energetics. From the calculated adsorption energies, we found that the pristine Sn3C2 monolayer and 3d TM has desirable properties for removal of the considered molecules based on their high adsorption energy, however the 4d TM 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 Sn3C2 monolayer. 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–Sn3C2 monolayers are good recoverable scavengers for the CO, CO2, NO, NO2, and SO2 molecules. The current theoretical calculations provide new insight on the effect of TM adatoms on the structural, electronic, and magnetic properties of the Sn3C2 monolayer and different transition metal adatom as well as shed light on their application as gas sensors/scavengers.