Adsorption characteristics of acid gases (NO, NO2, SO2 and SO3) on different single-atom nickel adsorbent: A first-principles study

Single-atom nickel adsorbent supported with different graphene-based substrates is supposed as a novel material for the adsorption and detection of acid gases (NO, NO2, SO2 and SO3). In this work, the adsorption characteristics, including adsorbent structures, adsorption configurations, adsorption energy, magnetic properties and thermodynamic properties, are investigated through density functional theory (DFT) calculations. According to the charge transfer and hybridization characteristics calculated by the electron density difference maps and the density of states, the binding mechanisms of four kinds of acid gases on different single-atom nickel adsorbents are explored. The calculated results indicate that NO, NO2, SO2 and SO3 can stably be adsorbed on single vacancy graphene with three nitrogen atoms doped (Ni-SVN3/GN) graphene adsorbent, and the values of the adsorption energy are -3.51 eV, -2.50 eV, -1.72 eV and -2.37 eV, respectively. EDDs, DOS and magnetic moment are calculated to reveal the electronic transfer in the whole process, which show that gas molecules acquire electrons and metal atom contributes electrons. Based on theoretical results, it can conclude that Ni-SVN3/GN is the most suitable adsorbent for acid gas removal. The theoretical study can guide the development of new materials for the removal of toxic gases.