MgO(001)表面负载CrW_2O_9团簇构型和电子结构的理论研究  

Theoretical Study on the Geometry and Electronic Structure of CrW_2O_9 Clusters Supported on the MgO(001) Surface

作　　者：张会[1] 朱佳[1] 樊跃华 章永凡 

机构地区：[1]江西师范大学化学化工学院,江西南昌330022 [2]福州大学化学学院,福建福州350116

出　　处：《江西师范大学学报（自然科学版）》2017年第4期432-440,共9页Journal of Jiangxi Normal University(Natural Science Edition)

基　　金：国家自然科学基金(21403094);江西省自然科学基金(20142BAB216031);江西师范大学博士启动基金资助项目

摘　　要：采用基于第一性原理的分子动力学与量子力学相结合的方法,对CrW_2O_9团簇在MgO(001)完整表面的吸附构型、稳定性以及电子结构进行了系统的研究.研究结果表明,CrW_2O_9团簇通过Cr、W以及O原子与MgO(001)表面作用,并可能以六元环、帽状或双环结构沉积在MgO(001)表面,其中热力学最稳定的吸附构型为CrW_2O_9团簇以六元环的结构吸附在MgO(001)完整表面.吸附后,有较多的电子从表面转移到团簇,与W3O9/MgO(001)体系相比,CrW_2O_9团簇的电子态出现在MgO(001)表面的带隙中,且主要为Cr 3d轨道的贡献,这将对体系的催化性能产生显著影响.The configuration,stability and electronic structure of CrW_2O_9 clusters deposited on the MgO( 001) surface have been investigated using first-principles molecular dynamic simulations combined with quantum mechanical calculations. The results show that,the CrW_2O_9 clusters interact with the MgO( 001) surface by Cr,W,O atoms and the CrW_2O_9 clusters assume three different structures including six-number ring,cap-shaped and dual-ring structures when deposited on MgO( 001) surface. The most stable configuration is that CrW_2O_9 cluster adsorption on the perfect MgO( 001) surface with a six-number ring. After deposition,obvious electrons are transferred from MgO( 001) surface to the CrW_2O_9 cluster. Compared with W3O9/MgO( 001) system,the states of CrW_2O_9 cluster appear in the gap of MgO( 001) surface,mainly derived from Cr 3d state,which will have significant impacts on the catalytic properties.

关 键 词：CrW2O9团簇 MgO(001)表面 密度泛函理论 构型和电子结构 

分 类 号：O641[理学—物理化学]