Co-adsorption of O2 and H2O on α-uranium (110) surface: A density functional theory study

• 来源期刊: 中国物理B（英文版）
• 关键词: co-adsorption α-U(110) surface DFT+U inhibition mechanism
• 年，卷（期）: 2018,（7）
• 页码范围: 476-483
• 页数: 8页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/7/076501

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 toα-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 ofα-uranium bulk well. Of all 7 low index surfaces ofα-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.