Effects of electric field and biaxial strain on the (NO2, NO, O2, and SO2) gas adsorption properties of Sc2CO2 monolayer

Abstract

Herein, we present a first-principles study of the effects of electric field and biaxial strain on the adsorption properties of Sc2CO2 monolayer in respect of O2, SO2, NO, and NO2 gases. We calculated the optimized configuration, adsorption energy, charge transfer, band structure, and densities of states of the adsorption systems under various electric fields and biaxial strains. We found that the adsorption intensities of NO2, NO, O2, and SO2 on the Sc2CO2 monolayer decrease with increasing the positive electric field. However, the electric field of 0.408 ​V/Å is not large enough to cause the desorption of O2, SO2, NO, and NO2 molecules, and it does not change their chemisorption nature on the Sc2CO2 monolayer. On the other hand, the gas adsorption intensity increases with increasing the biaxial strain from −10% to 10%. The Sc2CO2 monolayer with the −10% compressive strain physisorbs NO2, NO, O2, and SO2 molecules as compared to the chemisorption on the pristine one. The biaxial strains ϵ≥2% change the selectivity in gas adsorption of Sc2CO2 monolayer to NO2 molecule, compared with the O2 molecule on the pristine Sc2CO2 monolayer. The present work suggests an effective way to obtain attractive gas adsorption properties of two-dimensional materials using strain engineering for future gas sensors, gas capture or toxic gas filtration applications.