NiM双金属和γ-Al_2O_3的相互作用及对CO_2吸附的影响

INTERACTION OF NiM WITH γ-Al_2O_3 SURFACE AND EFFECTS ON THE ADSORPTION OF CO_2

用密度泛函理论(DFT)研究了单金属Ni2及NiMn,NiFe,NiCo和NiCu四种双金属与γ-Al2O3之间的相互作用及其对CO2吸附的影响.通过计算NiM在MgO上结合能、电子结构以及CO2在NiM/γ-Al2O3上的吸附能发现:NiM和γ-Al2O3之间的作用是电子的,NiM和γ-Al2O3之间电子的转移数以及NiM的d-带中心的变化能表现了NiM和γ-Al2O3之间相互作用的强弱;NiM和γ-Al2O3之间相互作用的强弱直接影响催化剂对CO2的吸附能力,相互作用越强,CO2的吸附越强;除了NiCu/γ-Al2O3,其他三种负载型双金属对CO2的吸附能力均强于负载的单金属Ni催化剂,其中,NiFe/γ-Al2O3对CO2的吸附能力最强.

The interactions of NiM （M=Mn, Fe, Co, Ni and Cu） with γ-Al2O3 （110） surface and their effects on the adsorption of CO2 have been investigated by using density func- tional theory （DFT） slab calculations. On the basis of binding energies and electronic structures of NiM on γ-Al2O3 as well as the CO2 adsorption energies on NiM/γ-Al2O3, we can get that the interaction between NiM and γ-Al2O3 is electronic, the transferred charge between NiM and γ-Al2O3 as well as the d-band center of NiM can reflect the interaction of NiM with γ-Al2O3 well; the interaction between NiM and γ-Al2O3 affects the adsorption ability of catalyst to CO2 directly, the stronger the interaction of NiM with γ-Al2O3is, the stronger of CO2 adsorption is; bimetal catalysts all show stronger CO2 adsorption than pure Ni catalyst except NiCu/γ-Al2O3, and NiFe catalyst shows the strongest adsorption ability to CO2.