Ab initio prediction and characterization of Hf2CO2 monolayer as a promising adsorbent to capture toxic AsH3 gas

Abstract Using first-principles calculation, we have studied the adsorption of AsH3 molecule on Hf2CO2 monolayer and a physisorption nature is shown with a moderate adsorption energy. This binding strength is hardly affected by pre-adsorbed H2O molecules and other functional group (OH, F) doped in the sheet, while the presence of oxygen vacancy on Hf2CO2 monolayer greatly promotes the AsH3 adsorption. Notably, applying external electric fields can realize the reversible storage of toxic AsH3 molecule by effectively modulating its adsorption strength with Hf2CO2 monolayer via dipole polarization. Moreover, monolayer Hf2CO2 shows an excellent adsorption capability and a steady binding strength toward AsH3 molecules, as well as a good stability at room temperature. These features highlight the promise of Hf2CO2 monolayer as an appealing candidate of toxic arsine adsorbents at room temperature.