Identification of potential metal oxides for NO2 capture: A density functional theory study

Air pollution issues have become inevitable, and it is necessary to prepare ways to prevent them from eventually affecting human health. This study thermodynamically investigated the NO₂ capture materials based on metal oxide systems using first-principles approaches. In particular, the NO₂ capture performances of the seven compounds CaO, MnO, NiO, SrO, BaO, TiO₂, and SnO₂ were assessed. Herein, BaO and SrO were found to possess the ability to capture NO₂ until the temperature of 757 and 691 K, respectively, at pressures of 0.001-bar NO₂ and 0.01-bar O₂. Furthermore, NO₂ adsorption on a BaO–SrO alloy system was systematically analyzed. The NO₂ adsorption strength on the alloy was found to be −1.732 eV, indicating that NO₂ is chemisorbed on this system. Bader charge results also demonstrated the interactions between the NO₂ adsorbate and the BaO/SrO/BaO(1 0 0) adsorbent.