氟、硅掺杂对CeO_(2)(001)表面结构及还原性能影响的第一性原理研究  

First Principles Study on Effect of Fluorine,Silicon Doping on Structure and Reduction Property of CeO_(2)(001)Surface

作　　者：贾慧灵[1,2] 卢元 吴锦绣 谭心 邵祺[1] 任元[1] Jia Huiling;Lu Yuan;Wu Jinxiu;Tan Xin;Shao Qi;Ren Yuan(College of Mechanical Engineering,Inner Mongolia University of Sciences and Technology,Baotou 014010,China;Key Laboratory of Green Extraction and&Eficient Utilization of Light Rare-Earth Resources,Ministry of Education,Baotou 014010,China;College of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,China)

机构地区：[1]内蒙古科技大学机械工程学院,内蒙古包头014010 [2]轻稀土资源绿色提取与高效利用教育部重点实验室,内蒙古包头014010 [3]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《中国稀土学报》2023年第4期794-801,I0005,共9页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(51965053);内蒙古自然基金项目(2018MS02016)资助。

摘　　要：使用DFT+U的方法研究了F,Si掺杂CeO_(2)(001)表面的结构和电子结构,分析了F,Si掺杂对CeO_(2)(001)表面还原性能的影响。结果表明:F,Si掺杂的CeO_(1.963)(001)体系中表层氧空位形成能均小于次表层氧空位形成能。CeO_(1.963)F_(0.037)(001)面的氧空位形成能比CeO_(1.963)(001)面的要大,而Ce_(0.926)Si_(0.074)O_(1.963)(001)面的氧空位形成能比CeO_(1.963)(001)面的要小。Si掺杂的CeO_(2)(001)面局部晶格发生畸变,结构变得不稳定。CeO_(2)(001)面的Ce 4f电子态部分占据费米能级,禁带宽度变为零,并且上下自旋电子态不对称;CeO1.926F0.037-sur面的Ce 4f电子态和O 2p电子态分布变得局域,费米能级处产生0.853 eV的带隙;Ce_(0.926)Si_(0.074)O_(1.963)^(-sur)面的电子态向低能级方向移动,Ce 4f的上自旋电子态和O 2p的下自旋电子态占据费米能级。Ce_(O1.926)F_(0.037)-sur面中氧空位最近邻的铈离子分别从掺杂F原子和氧空位处得到0.022e和0.038e电子;Ce_(0.926)Si_(0.074)O_(1.963)-sur面中氧空位最近邻的铈离子分别从掺杂Si原子和氧空位处得到0.102e和0.021e电子。The structure and electronic structure of F,Si-doped CeO_2(001)surface were studied by DFT+U method,and the effects of F,Si doping on the reduction properties of CeO_2(001)surface were analyzed.The results show that the formation energy of surface oxygen vacancy is less than that of subsurface oxygen vacancy in the F,Si-doped CeO_(1.963)(001)surface.The oxygen vacancy formation energy of CeO_(1.963)F_(0.037)(001)surface is larger than that of CeO_(1.963)(001)surface,while the oxygen vacancy formation energy of Ce_(0.926)Si_(0.074)O_(1.963)(001)surface is smaller than that of CeO_(1.963)(001)surface.The local lattice of Si-doped CeO_2(001)surface is distorted and the structure becomes unstable.The electronic state of Ce 4f partially occupies the Fermi level,the band gap becomes zero,and the upper and lower spin electronic states are asymmetric on the CeO_2(001)surface.The distribution of Ce 4f and O 2p electronic states becomes localized,and a band gap of 0.853 eV is generated at the Fermi level on the CeO_(1.926)F_(0.037)-sur surface.The electronic state of Ce_(0.926)Si_(0.074)O_(1.963)-sur surface moves to the low energy level,and the upper spin electronic state of Ce 4f and the lower spin electronic state of O 2p occupy the Fermi level.The Ce ion nearest to the oxygen vacancy in the CeO_(1.926)F_(0.037)-sur surface obtained 0.022e and 0.038e electrons from the doped F atom and the oxygen vacancy,respectively.The Ce ion nearest to the oxygen vacancy on Ce_(0.926)Si_(0.074)O_(1.963)-sur surface obtained 0.102e and 0.021e electrons from the doped Si atom and the oxygen vacancy,respectively.

关 键 词：CeO_(2)(001)表面 F Si掺杂 原子结构 电子结构 第一性原理 

分 类 号：O655.4[理学—分析化学]