First-principles study of active element (K, Ca, Na, Y) adsorption on Fe2B (002) surface

Traditional experiments have a certain degree of trial and error, and the cost is high. Compared with the traditional experimental method, this work adopts the first-principles method to simulate the controlled growth of active elements adsorbed on the surface of Fe2B, and the adsorption energy, electronic structure and bond formation of active atoms (K, Ca, Na, Y) on the Fe2B (002) surface are analyzed. The results showed that, based on adsorption energy, K atoms were most easily adsorbed on the surface of Fe2B (002) with the best adsorption performance compared to Ca, Na and Y atoms. The most stable adsorption sites at different termination ends were also different. For the adsorption of the active atom at the B termination, the most stable adsorption site was the bridge site (B) compared to the other sites. For the Fe termination, its stable adsorption site varied with the activity energy of different active elements. By analyzing the electronic structure and bonding, it was found that the K, Ca, Na and Y atoms were more metallic at the Fe termination than at the B termination. K, Ca, Na and Y atoms formed mixed ionic/metal bonds with the Fe termination. Mixed ionic/metallic bonds were formed between the Y atoms and the B termination, while ionic bonds were formed between the K, Ca, and Na atoms and the B termination. [Display omitted] •K atom is easier adsorbed on the surface of Fe2B (002) relative to Ca, Na, and Y atoms.•All the adsorbed elements (K, Ca, Na, Y) are chemically adsorbed during the adsorption process.•K, Ca, Na and Y atoms are more metallic at the Fe terminations than that at the B terminations.•K, Ca, Na and Y atoms form mixed ionic/metallic bonds with the Fe terminations. K, Ca, Na and Y atoms form mixed ionic bonds with the B terminations.