Computational study on nickel doped encapsulated Mg, K, Ca on pristine C₂₄ nanocage for gas sensing applications

Intense attention have been channeled into environmental sustainability due to the high emission of greenhouse gases therefore, this investigatiom focuses on the adsorption and sensing properties of nickel doped encapsulated Mg, K, Ca on pristine C₂₄ nanocage for CO₂, NO₂ and SO₂ gases using density functional theory (DFT) method. Two adsorption models were designed due to the shape of the gas molecules, interacting to the doped atom, the DFT/TPSSh/Gen method was utilized to explore the adsorption properties from the perspective of geometry analysis, adsorption energy (E_ads), electronic properties, visual study of weak interactions, dipole moment, and recovery time for reusability were considered. This work incorporated a comprehensive reference for the selectivity of the adsorbents’ modification towards the effective sensing of these toxic gases. Thus, the electronic properties confirms the conductivity on modification of surface with dopant. Also, the nature of interaction as reveal by the QTAIM analysis was non-covalent in nature and was further confirmed by the analysis of the non-covalent interaction (NCI). Moreso, the reusability analysis confirms surface sensing properties. Adsorption energies; −3.67, −2.48, −3.89, −2.50, −3.82, −3.67 eV, were reported for NO₂–Ni@MgC, CO₂–Ni@KC, NO₂–Ni@KC, CO₂–Ni@CaC, NO₂–Ni@CaC, SO₂–Ni@CaC respectively. Moreover, the aforementioned analyses demonstrate the significant impact on the adsorption models most especially NO₂–Ni@KC. Hence, Ni@KC and Ni@CaC shows promising sensitivity towards the gas molecules than Ni@MgC. Based on our theoretical results, the encapsulation of K, Ca, Mg, and late transition metal dopant enhances the adsorbents, which induced the improvement in surface properties. The highest Eads was observed at M3a at −5.11 eV and the least at M1 at −2.11 eV all for SO2 adsorption.