Co-adsorption of O_2 and H_2O on α-uranium(110) surface:A density functional theory study  

作　　者：Xin Qu Ru-Song Li Bin He Fei Wang Kai-Long Yuan 瞿鑫;李如松;何彬;王飞;袁凯龙(Xi'an High Technology Institute, Xi'an 710025, China)

机构地区：Xi＇an High Technology Institute,Xi＇an 710025,China

出　　处：《Chinese Physics B》2018年第7期417-423,共7页中国物理B（英文版）

基　　金：Project supported by the National Nature Science Foundation of China(Grant Nos.51401237,11474358,and 51271198)

摘　　要：First-principles calculations based on density functional theory corrected by Hubbard parameter U （DFT＋U） are applied to the study on the co-adsorption of O2 and H2O molecules to a-U（110） surface. The calculation results show that DFT＋U method with Ueff = 1.5 eV can yield the experimental results of lattice constant and elastic modulus of a-uranium bulk well. Of all 7 low index surfaces of a-uranium, the （001） surface is the most stable with lowest surface energy while the （110） surface possesses the strongest activity with the highest surface energy. The adsorptions of O2 and H2O molecules are investigated separated. The O2 dissociates spontaneously in all initial configurations. For the adsorption of H2O molecule, both molecular and dissociative adsorptionsoccur. Through calculations of co-adsorption, it can be confirmed that the inhibition effect of O2 on the corrosion of uranium by water vapor originates from the preferential adsorption mechanism, while the consumption of H atoms by O atoms exerted little influence on the corrosion of uranium.First-principles calculations based on density functional theory corrected by Hubbard parameter U （DFT＋U） are applied to the study on the co-adsorption of O2 and H2O molecules to a-U（110） surface. The calculation results show that DFT＋U method with Ueff = 1.5 eV can yield the experimental results of lattice constant and elastic modulus of a-uranium bulk well. Of all 7 low index surfaces of a-uranium, the （001） surface is the most stable with lowest surface energy while the （110） surface possesses the strongest activity with the highest surface energy. The adsorptions of O2 and H2O molecules are investigated separated. The O2 dissociates spontaneously in all initial configurations. For the adsorption of H2O molecule, both molecular and dissociative adsorptionsoccur. Through calculations of co-adsorption, it can be confirmed that the inhibition effect of O2 on the corrosion of uranium by water vapor originates from the preferential adsorption mechanism, while the consumption of H atoms by O atoms exerted little influence on the corrosion of uranium.

关 键 词：CO-ADSORPTION α-U（110） surface DFT＋U inhibition mechanism 

分 类 号：O647.31[理学—物理化学]