Adsorption of CO₂ on the Surface of Fe(111): A First-Principles Study

First-principle is used to study the structure parameters, adsorption energy, Bader charge, electronic density of states, charge-density transformation, and surface work function of CO₂ molecule at various adsorption sites on the Fe(111) surface based on Density Function Theory (DFT). Results show that the CO₂ molecule is absorbed on the Fe(111) surface by combining Fe–C and Fe–O multiple bonds. The type of adsorption of most configurations is chemisorption. The most stable structure is BS-Y, with an adsorption energy of −0.8115 eV. The order of stability of adsorption sites is bridge site > hcp site > fcc site > top site. Carbon dioxide mostly reacts with the uppermost two layers of Fe atoms and just partially with the lowermost two levels. In addition, the chemical bonds between CO₂ molecule and Fe atoms are covalent, and the response mechanism is the hybridization of C-2s, C-2p, O-2s, and O-2p orbitals with Fe-3p, Fe-3d, Fe-4s orbitals, forming new chemical bonds. The BS-Y configuration has the smallest increment of work function, indicating that the lowest escape energy is required for the electron to escape from the surface.