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Engineering Ni3+ Cations in NiO Lattice at the Atomic Level by Li+ Doping: The Roles of Ni3+ and Oxygen Species for CO Oxidation
ACS Catalysis ( IF 12.9 ) Pub Date : 2018-07-20 00:00:00 , DOI: 10.1021/acscatal.8b01692
Xianglan Xu 1 , Lin Li 1 , Jin Huang 1 , Hua Jin 2 , Xiuzhong Fang 1 , Wenming Liu 1 , Ning Zhang 1 , Hongming Wang 3 , Xiang Wang 1
Affiliation  

To investigate the Li+ doping effect on the structure and reactivity of NiO, a series of NiO catalysts doped by Li+ cations have been synthesized and probed by using CO oxidation as a model reaction. With a combination of experimental methods and DFT calculations, it has been revealed that the Li+ cations preferentially replace the lattice Ni2+ cations instead of directly refilling the Ni2+ vacancies in the cubic NiO lattice to form a solid solution structure below the lattice capacity. For samples possessing a pure solid solution phase, the Ni3+ cation amount increases with the increasing of lattice Li+ cation content, hence inducing the formation of larger quantities of surface mobile oxygen species. In addition, the surface reducibility and the CO adsorption and activation ability can be enhanced, accompanying the easier formation of surface oxygen vacancies and the extraction of surface active oxygen. Therefore, the intrinsic CO oxidation activity can be remarkably enhanced. In contrast, by the addition of excess Li+ cations above the lattice capacity, Li+ is present as an additional surface Li2CO3 phase, which evidently degrades the activity of the catalysts because of the loss of lattice Ni3+ cations and active oxygen sites. It is concluded in this paper that the best catalyst can be tailored at the atomic level by engineering the maximum amount of Ni3+ cations in the NiO lattice matrix with a pure solid solution phase by Li+ addition.

中文翻译:

Li +掺杂在原子水平上工程化NiO晶格中的Ni 3+阳离子:Ni 3+和氧物种对CO氧化的作用

为了研究Li +掺杂对NiO的结构和反应性的影响,已经合成了一系列由Li +阳离子掺杂的NiO催化剂,并以CO氧化为模型反应进行了探索。结合实验方法和DFT计算,发现Li +阳离子优先取代晶格Ni 2+阳离子,而不是直接重新填充立方NiO晶格中的Ni 2+空位,从而在晶格下方形成固溶体结构。容量。对于具有纯固溶相的样品,Ni 3+阳离子量随晶格Li +的增加而增加阳离子含量,因此诱导形成大量的表面可移动氧物种。另外,伴随着更容易形成表面氧空位和提取表面活性氧,可以提高表面还原性以及CO的吸附和活化能力。因此,可以显着提高固有的CO氧化活性。相反,通过在晶格容量之上添加过量的Li +阳离子,Li +作为附加的表面Li 2 CO 3相存在,由于晶格Ni 3+的损失,这明显降低了催化剂的活性。阳离子和活性氧位点。它是在本文中,最好的催化剂可以在原子水平上通过改造Ni的最大量被定制结束3+阳离子的氧化镍晶格矩阵与由李纯的固体溶液相+加成。
更新日期:2018-07-20
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