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.