Theoretical investigation of metal oxides for SO2 capture through first-principles calculations

Abstract

Atmospheric pollution is an accelerating environmental issue. Thus, methods to mitigate this problem are highly important. In this study, metal oxide‐based materials for capturing SO2 were theoretically identified using first‐principles calculations. In specific, the thermodynamic properties of MnO, Na2O, K2O, and Ag2O for capturing SO2 were assessed by computing their vibrational density of states. The rank of the maximum temperature for capturing SO2 as sulfites in decreasing order was K2O > Na2O > MnO > Ag2O at a wide range of SO2 pressure. For Na2O and K2O that showed a higher range of SO2 capture temperatures as sulfites, the maximum temperature of these two compounds for capturing SO2 as sulfates was further explored. The maximum temperature of the metal oxides for capturing SO2 changed upon pressurization of metal oxides. The maximum temperature of each metal oxide increased with increasing positive pressure (i.e., compression) and decreased with increasing negative pressure (i.e., expansion). This study thermodynamically assesses the performance of MnO, Na2O, K2O, and Ag2O for capturing SO2. The rank of the maximum temperature for capturing SO2 in decreasing order was K2O > Na2O > MnO > Ag2O at a wide range of SO2 pressure. In the presence of oxygen, sulfate formation was preferred to sulfite formation.