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在密度泛函理论框架下,采用嵌入点电荷簇模型研究了NO在MgO(001)完整和缺陷表面上的吸附。研究结果表明:具有氧缺陷结构表面的催化活性较高,有利于NO键的削弱;当另一个NO分子进攻已吸附的NO分子时,NO键将进一步削弱,直致断裂,并伴有N2O产生,这与UPS和MIES实验观察到的现象一致。Mulliken布居分析指出,底物电子向NO转移,并填充到NO的*反键轨道上,从而导致NO键的削弱,并形成NO-。这也是可能导致形成NO-的原因。研究还表明,具有镁缺陷的MgO(001)表面对NO的解离没有催化活性。
In the framework of density functional theory, the adsorption of NO on the surface of MgO (001) intact and defect was studied by using the embedded point charge cluster model. The results show that the surface of the oxygen-deficient structure has higher catalytic activity and is conducive to the weakening of the NO bond. When another NO molecule attacks the adsorbed NO molecule, the NO bond will be further weakened, ruptured and associated with N2O production , Consistent with the observations of UPS and MIES experiments. Mulliken’s population analysis indicated that the substrate electrons migrated to NO and filled into the * antibonding orbit of NO, leading to the weakening of the NO bond and the formation of NO-. This is also the reason that NO- may form. The study also showed that MgO (001) surfaces with magnesium defects have no catalytic activity for the dissociation of NO.