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.