CO和CO2在UO2(111)表面吸附和解离的第一性原理和分子动力学研究
First-Principles and ab-initio Molecular Dynamics Simula-tion Research on Adsorption and Dissociation of CO and CO2 Molecules on U02(111)Slab
李俊炜 1贾维敏 2刘崇 3李沛尧 3李正操3
作者信息
- 1. 清华大学材料学院,北京 100084;西安高科技研究所,陕西西安 710025
- 2. 西安高科技研究所,陕西西安 710025
- 3. 清华大学材料学院,北京 100084
- 折叠
摘要
基于密度泛函理论(DFT)的第一性原理计算,在计算中加入Hubbard项进行校正,探究了 CO和CO2分子在UO2(111)表面的吸附和解离,分析了不同构型下的静态和动态吸附机理,吸附位点包括顶位、空位、桥位.在静态计算中,探究了吸附过程中多种吸附参数的变化,如吸附构型、吸附能、电荷转移等.利用第一性原理分子动力学(AIMD),探究了特定构型下CO2分子的解离过程及差分电荷密度变化.结果表明,CO分子的吸附可分为2种类型:(1)自发吸附,包括化学和物理吸附;(2)非自发吸附.CO2分子的吸附仅表现为自发吸附的化学吸附及非自发吸附,无物理吸附.CO和CO2分子的最优吸附构型均为短桥位垂直(B-short-Ver)吸附.此外,0K下CO2分子在UO2(111)表面的B-short-Ver和长桥位垂直吸附构型吸附后会自发解离.AIMD模拟结果表明,这2种构型在300K下均发生解离.
Abstract
The adsorption and dissociation of CO and CO2 molecules on UO2(111)slab were investigated by the first-principles calculations based on density functional theory with the addition of Hubbard term for calculation correction.Different static and dynamic adsorption mechanisms under different configurations were analyzed,and the adsorption sites included top,hollow,and bridge sites.In the static calculations,the variation of adsorption parameters,such as adsorption configuration,adsorption energy,and charge transfer,during adsorption process was investigated.ab-initio molecular dynamics(AIMD)was employed to study the dissociation process of CO2 molecules and the changes in charge density difference.Results show that the adsorption of CO molecules can be categorized into two types:(1)stable adsorption,including chemical and physical adsorptions;(2)unstable adsorption.The adsorption types of CO2 on UO2(111)slab only include the chemical adsorption of stable adsorption and unstable adsorption.No physical adsorption exists.The optimal configuration for the adsorption of both CO and CO2 molecules is short-bridge vertical(B-short-Ver)adsorption.Additionally,at 0 K,the CO2 molecules at the configurations related to B-short-Ver adsorption and long-bridge vertical adsorption on UO2(111)slab spontaneously dissociate after adsorption.AIMD simulation results show that both configurations dissociate at 300 K.
关键词
二氧化铀/化学吸附/DFT+U/桥位垂直Key words
uranium dioxide/chemical adsorption/DFT+U/bridge vertical引用本文复制引用
基金项目
国家自然科学基金(11975135)
国家自然科学基金(12005017)
National Basic Research Program of China(2020YFB1901800)
出版年
2024
NETL
NSTL
万方数据