铜锌镁铝四元水滑石的微观结构及其姜-泰勒畸变  

Microstructure and Jahn-Teller Effect of Cu-Zn-Mg-Al Layered Double Hydroxides

作　　者：王力耕[1] 施炜[1] 姚萍[1] 倪哲明[1] 李远[1] 刘娇[1] 

机构地区：[1]浙江工业大学化学工程与材料学院,先进催化材料实验室,杭州310032

出　　处：《物理化学学报》2012年第1期58-64,共7页Acta Physico-Chimica Sinica

摘　　要：采用密度泛函理论(DFT),选取CASTEP程序模块,对铜锌镁铝四元水滑石[(M)-IV-LDHs(M=Cu,Zn,Mg,Al)]周期性模型进行几何全优化,从各体系的结构参数、电子排布、Mulliken电荷布居、结合能、氢键等方面,研究了体系中的姜-泰勒效应、氯离子位置对层板畸变及体系稳定性的影响.优化结果表明,姜-泰勒效应不仅存在于d轨道未排满的Cu2+中,也存在于理论上d轨道排满的Zn2+与p轨道未排满的Mg2+中.氯离子排在金属上方的体系,其金属畸变程度大于氯离子排在非金属上方的体系.同时,对于本文选取的8个CuAl-IV-LDHs体系,结合能绝对值按照1-8号逐渐降低,体系的稳定性下降,最终转变为不稳定的压扁的八面体构型.这有助于从理论上对含铜四元水滑石的姜-泰勒效应进一步认识.We propose a periodic interaction model for layered double hydroxides, CuZnMgAl quaternary hydrotalcites [（M）-IV-LDHs （M=Cu, Zn, Mg, Al）]. Based on density functional theory the geometries of CuZnMgAl quaternary hydrotalcites were optimized using the CASTEP program. The impacts of the Jahn-Teller effect and the location of chlorine over the layer distortion and stability were investigated by analyzing the geometric parameters, the electronic arrangement, charge populations, binding energies, and hydrogen-bonding. The optimization results showed that the Jahn-Teller effect does not only exist in Cu2＋ when its d orbital is partially filled but it also exists in Zn2＋ when its d orbital is full as well as in Mg2＋ when its p orbital is partially filled. Systems where the chloride is located above the metal show greater metal distortion than systems with anions located above non-metals. Eight systems （Nos. 1-8） were chosen for our work and their absolute binding energy values were found to decrease gradually while the stability of the systems became worse. Finally, the systems became unstable and were found to be flattened octahedral forms. These results help us to better understand the Jahn-Teller effect in copper-containing IV-LDHs from theory.

关 键 词：四元含铜水滑石 密度泛函理论 姜-泰勒效应 

分 类 号：O641.4[理学—物理化学]