摘要
构建一价阴离子(X=F-,Cl-,Br-,I-,NO-3,OH-)插层铜锌镁铝四元水滑石(CuZnMgAl-X)周期性计算模型,采用密度泛函理论(DFT),选取CASTEP程序模块,对体系进行几何全优化,从结合能、结构参数、Mulliken布居、氢键布居、态密度等角度研究了不同层间阴离子的分布形态以及其对主客体间超分子作用的影响.结果表明,随着CuZnMgAl-X体系层间阴离子电负性的减弱,电子逐渐从层间阴离子向层板发生转移,主客体间静电作用力逐渐减小,氢键强度逐渐降低,禁带宽度逐渐变窄,体系电子更易向高能级发生跃迁,稳定性逐渐下降.此外,Cu的掺杂使得CuZnMgAl-X体系的价带顶向高能量处发生偏移,禁带宽度较传统水滑石体系更窄,稳定性更低,进一步解释了含铜水滑石较难合成的原因.
A periodic interaction model with different intercalated anions （X=F,Cl,Br,I,NO 3,OH） is proposed for the CuZnMgAl quaternary hydrotalcites （CuZnMgAl-X）.Based on density functional theory,the CuZnMgAl-X geometry was optimized using the CASTEP program.The distribution of anions in the interlayer,and the supra-molecular interaction between host layer and guest anions were investigated by analyzing binding energies,geometric parameters,Mulliken populations,hydrogen-bonding and densities of states.A decreased electronegativity of interlayer anion caused a transfer of charge from guest anions to host layer and a gradual decrease in the strength of electrostatic interaction and hydrogen bonding.The system band gap narrowed,electrons transferred to higher energy levels more easily,and the overall stability of the system decreased.The Cu dopant caused a deviation in CuZnMgAl-X valence band to high energies.Compared with traditional layered double hydroxides,the band gap narrowed and stability decreased,accounting for the difficulty in preparing copper-containing hydrotalcites.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2013年第3期491-497,共7页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(51002137)资助项目~~
关键词
密度泛函理论
铜锌镁铝四元水滑石
不同层间阴离子
超分子作用力
Density functional theory
Cu-Zn-Mg-Al quaternary hydrotalcite
Different intercalated anions
Supra-molecular interaction
