Catalytic Activity of Au and Au2 on the h-BN Surface: Adsorption and Activation of O2
Catalytic Activity of Au and Au2 on the h-BN Surface: Adsorption and Activation of O2
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DOI：
10.1021/jp300684v
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发表时间：
2012-04-26
影响因子：
3.7
通讯作者：
Taketsugu, Tetsuya
中科院分区：
文献类型：
--
作者：
Gao, Min;Lyalin, Andrey;Taketsugu, Tetsuya
利用密度泛函理论研究了六方氮化硼（h-BN）表面负载Au和Au-2的结构、电子和催化性质.结果表明，O-2在h-BN负载的Au和Au-2上的吸附和催化活性受其与载体之间的电子推动和施主/受主相互作用的影响。它表明，即使是弱的相互作用的Au和Au-2与无缺陷的“惰性”的h-BN表面可以有一个异常强烈的影响上的分子氧的结合和催化活化。这种效应是由于负载的Au和Au-2的5d轨道与N-p（z）轨道的混合而发生的。虽然无缺陷的h-BN表面并不作为负载的O-2-Au的良好电子供体，但它促进了电子从Au转移到O-2，将电子从金推到吸附的氧。在有缺陷的h-BN表面的情况下，Au和Au-2可以被N或B空位和杂质点缺陷有效地捕获。表面缺陷上的强吸附伴随着大的电荷转移到/从吸附质。负载型Au和Au-2上过量的正电荷或负电荷可显著提高其催化活性。因此，h-BN表面（原始的或有缺陷的）不能被认为是Au和Au-2的惰性载体。
The structural, electronic, and catalytic properties of Au and Au-2 supported on the pristine and defected hexagonal boron nitride (h-BN) surface have been studied theoretically using density functional theory. It is demonstrated that adsorption and catalytic activation of O-2 on the h-BN supported Au and Au-2 can be affected by the interaction with the support via electron pushing and donor/acceptor mechanisms. It is shown that even weak interaction of Au and Au-2 with the defect-free "inert" h-BN surface can have an unusually strong influence on the binding and catalytic activation of the molecular oxygen. This effect occurs due to the mixing of the 5d orbitals of the supported Au and Au-2 with the N-p(z) orbitals. Although the defect-free h-BN surface does not act as a good electron donor for the supported O-2-Au, it promotes an electron transfer from the Au to O-2, pushing electrons from the gold to the adsorbed oxygen. In the case of the defected h-BN surface, Au and Au-2 can be trapped effectively by N or B vacancy and impurity point defects. Strong adsorption on the surface defects is accompanied by the large charge transfer to/from the adsorbate. The excess of the positive or negative charge on the supported Au and Au-2 can considerably promote their catalytic activity. Therefore, the h-BN surface (pristine or defected) cannot be considered as an inert support for Au and Au-2.