Density functional theory study of CO2 adsorption on metal (M=Li, Al, K, Ca) doped MgO

In this work, metal doping with magnesium oxide (M/MgO (M=Li, Al, K, Ca)) was constructed by density functional theory (DFT) methods to investigate the functions of crystal plane and doping on CO2 adsorption properties and mechanism. DFT calculations show that the appropriate crystal plane and the doping metal can improve the adsorption properties of MgO on CO2, and the effect of different planes and different types of doped metals on CO2 adsorption properties varies significantly. CO2 adsorption on the MgO(110) plane is more favorable than on the MgO(100) plane, exhibiting an adsorption energy of -1.834 eV. The structural stability and adsorption properties of MgO are enhanced through the doping of metals (Li, Al, K, Ca), with K being the superior one due to its adsorption energy of -2.148 eV. The selection of crystal plane and doped metal enhances charge transfer at interfaces, resulting in a noteworthy improvement in CO2 adsorption on M/MgO(110) plane. Additionally, the adsorption mechanism transitions from physisorption to chemisorption on the MgO(110) plane. This work combines the dual modification of crystal plane and doped metal to provide some references for the experimental study of CO2 adsorption by MgO.