N2O decomposition on MgO and Li/MgO catalysts:: A quantum chemical study

被引：34

作者：

Lu, X ^{[1
]}

Xu, X ^{[1
]}

Wang, NQ ^{[1
]}

Zhang, QN ^{[1
]}

机构：

[1] Xiamen Univ, Dept Chem, Inst Phys Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China

来源：

JOURNAL OF PHYSICAL CHEMISTRY B | 1999年 / 103卷 / 17期

关键词：

D O I：

10.1021/jp982384+

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Ab initio embedded cluster model calculations have been performed to study the decomposition of N2O on MgO and Li/MgO catalysts. The following has been found. (i) On MgO(001) terrace atomic oxygen is adsorbed on top of the O-5c anions, while on corners or steps the preferable mode is for atomic oxygen to bridge over the low-coordinated O-XC-Mg-YC (X, Y = 3, 4) ion pairs. The adsorption of atomic oxygen leads to the formation of a peroxide ion. (ii) N2O decomposition over a five-coordinate terrace anion would be possible, while the defective O-XC-Mg-YC (X, Y = 3, 4) ion pairs are more active to decompose N2O. The activity of the Q(XC)-Mg-YC (X, Y = 3, 4) ion pairs toward N2O decomposition could be assigned in the order O-3C-Mg-3C > O-4C-Mg-3C > O-3C-Mg-4C > O-4C-Mg-4C (iii) When the MgO catalyst is doped with Li, the so-called [Li+O-] centers are found to be active for decomposing N2O, and the decomposition of N2O on the active [Li+O-] center leads to the formation of the superoxide anion. This accounts for the higher reactivity and selectivity of the Li/MgO catalyst.

引用

页码：3373 / 3379

页数：7

共 43 条

[1] Interaction of methane with a [Li](0) center on MgO(100): HF, Post-HF, and DFT cluster model studies [J].