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采用密度泛函方法研究了Fe(100)表面Cu单层膜上CO的吸附,直接解离,氢助解离以及C-C偶合反应。相比洁净的Fe(100)表面,在Fe(100)的单层Cu膜上,CO的吸附和活化都减弱了。特别是,相比Fe(100)上CO的解离能垒1.08 eV,铜单层膜上CO解离能垒高达2.4 eV。在H原子共吸附的情况下,Fe(100)上CO解离在动力学上更容易了一些,而在Cu单层膜上,CO的解离通过形成甲酰基(CHO)大大的加快了,能垒降低到了0.92 eV,接近Fe(100)上的0.81 eV。同时,我们发现Cu单层膜上C-H键C-C键的形成比Fe(100)上能垒低,且放热量更大。
The adsorption, direct dissociation, hydrogen-assisted dissociation and C-C coupling reaction of CO on the Cu (Cu) single layer film on Fe (100) surface were investigated by density functional theory. Compared with the clean Fe (100) surface, the adsorption and activation of CO on Fe (100) monolayer Cu films are weakened. In particular, the CO dissociation barrier on the Cu monolayer is as high as 2.4 eV compared to 1.08 eV for the dissociation energy of CO on Fe (100). In the case of coexistence of H atoms, the dissociation of CO on Fe (100) is somewhat more kinetic, whereas on the Cu monolayer, CO dissociation is greatly accelerated by the formation of formyl groups (CHO) The energy barrier is reduced to 0.92 eV, approaching 0.81 eV on Fe (100). At the same time, we found that the formation of C-C bond on Cu monolayer is lower than that of Fe (100) and the heat release is larger.