CO2 adsorption on a K-promoted MgO surface: A DFT theoretical study

Abstract

The primary cause of global warming is the emission of greenhouse gases such as CO₂. So reducing CO₂ emissions is vital. This paper investigates the impact of the atom K as a promoter of MgO on the CO₂ adsorption properties using the DFT theoretical computational method. By analyzing the adsorption energy, bader charge as well as the density of states and COHP, it was found that K-promoting the MgO (100) surface resulted in a redistribution of charge on the MgO surface and enhanced CO₂ adsorption compared to the pure MgO surface. The presence of K atoms causes orbital hybridization among O (CO₂) and Mg atoms, O (CO₂) atoms and K atoms, and the surface O atoms and K atoms. These interactions lead to the formation of (MgO)Mg-O(CO₂) and (CO₂)O−K−O(MgO) chemical bonds. The adsorption energy of CO₂ on the K-promoted MgO surface increased from -0.32 eV to -1.01 eV compared to the pure surface, enhancing the adsorption of CO₂.