Author(s): WEI Liu-ting, TONG Zhang-fa, WU Dong-hai, ZHOU Si-chen, WANG Hai-chen, LUO Tao-peng, TANG Bi-yu, School of Chemistry and Chemical Engineering, Guangxi University, Guangxi Engineering Academy of Calcium Carbonate Industrialization
Pages: 670-674+680
Year: 2015 Issue:  6
Journal: Guangxi Sciences
Keyword:  Calcium oxide; surface energy; stability; electronic structure; first-principles;
Abstract: 【Objective】The surface energy,surface relaxation and electronic structure of(100),(110)and Ca-terminated(111)surfaces for CaO were systemically investigated.【Methods】The surface properties were calculated using first-principle based on density functional theory.Sixlayer slab model with 15 A vacuum was used in all the calculations.【Results】The calculated lattice constants of bulk CaO agree reasonably with experimental values.The surface energy of(100)surface is lowest,suggesting that(100)surface is the most stable and is easy to expose outside.The surface energy of(110)surface is lower than that of Ca-terminated(111)surface,whereas the Ca-terminated(111)surface is most unstable due to the highest surface energy.The relaxation of(100)surface is the smallest,suggesting the strongest stability.Relaxation degree of(110)surface is between(100)and Ca-terminated(111)surfaces.In(100)surface,the over-laps of Ca-O and Ca-Ca electron clouds are more obvious than those of(110)surface,while the Ca-Ca overlap in Ca-terminated(111)surface is relatively weaker,indicating that surface stability is gradually lowered from(100),(110)to Ca-terminated(111)surface.【Conclusion】The(100)surface for CaO exhibits the most favorable properties,followed by(110)surface,and Ca-terminated(111)surface is most unstable.