外电场对NO在Graphene负载的Pd单原子上的吸附特性的调控

Tuning the adsorption properties of NO on Pd single atom supported by Graphene

本研究中,通过基于密度泛函理论的第一性原理并考虑范德华力修正计算了Graphene负载的Pd单原子界面特性以及NO的吸附特性(包括吸附构型的结构参数、吸附能和电子结构等),并着重研究了电场对其吸附特性的调控规律及其内在机理.结果表明:1)NO在Pd/Graphene上能够形成较强的化学吸附,吸附能为1.09 eV.吸附的NO分子中的N-O键拉长.Pd-d态与NO-p态的强杂化作用都表明NO分子在Pd-Graphene上被活化.2)在电场作用下Graphene负载的单原子Pd上的电荷随施加的电场逐渐变化.3)跟没有施加电场的NO吸附的体系相比,当对NO吸附体系施加沿Z正方向的电场时,NO的吸附增加,吸附的NO从衬底获得更多的负电荷,而Pd所带的正电荷逐步减少;当对NO吸附体系施加沿Z负方向的电场时,NO的吸附减弱,吸附的NO从衬底获得的负电荷逐渐减少,而Pd所带的正电荷逐步增加.4)外加电场能够有效地调控NO的吸附特性,并调控NO与衬底之间的电荷转移进而调控其电子结构.

In this paper,using the DFT-D method to simulate the interfacial properties of the Pd/Graphene,the adsorption properties of NO on Pd/Graphene as well as the effect of the external electric field are studied.It is found that:1)the adsorption of the NO on Pd/Graphene is very strong with big adsorption energy of 1.09 eV,and the N-O bond is enlarged during the adsorption.The strong hybridized interaction between Pd-d states and NO-p states is the origin of the strong interaction between NO and Pd/Grpahene.2)The charge of the anchored Pd on Graphene is changed with the external electric field.3)Compare with the systems without external electric field,the adsorption of the NO on Pd/Graphene would be enhanced during the external electric field along the Z direction,and the adsorbed NO gets more electrons from the support.Otherwise,the adsorption of the NO on Pd/Graphene would be shrunk during the external electric field along the adverse Z direction,and the adsorbed NO gets less electrons from the support.4)The external electric field could effectively tune the adsorption properties of NO and the charge transfer between NO and the substrate to tune its electronic structure.