载铜活性炭吸附一氧化碳的密度泛函理论计算

应用密度泛函理论和相对论有效核势方法, 用C₁₆H₁₀, C₁₃H₉, C₁₂H₁₂原子簇模型模拟活性炭表面, 计算得到了CO在载铜活性炭上的吸附位、吸附构型和吸附能. 研究表明: 载铜活性炭吸附CO的过程, 本质上是Cu(I)通过σ-π配键与CO络合, 形成Cu—C键的过程. 载铜活性炭对CO的络合吸附能在50～60 kJ/mol之间, 远大于活性炭对CO的物理吸附能(9.15 kJ/mol), 因而络合吸附更稳定, 选择性也更高. Cu(I)选择吸附在活性炭表面的顶位和桥位, 一个Cu(I)至多可以吸附一个到两个CO分子, 但吸附一个CO比吸附两个CO稳定.

Density Functional Theory Calculations of Carbon Monoxide Adsorption on Activated Carbon Loaded with Cuprous Salt

In the paper, the density functional theory and the cluster model approach have been applied to study complex adsorption of carbon monoxide on activated carbon loaded with cuprous salt. The adsorption sites of bridge, top and hole on activated carbon have been modeled by C₁₆H₁₀, C₁₃H₉ and C₁₂H₁₂ clusters. The results show that adsorption of carbon monoxide on activated carbon loaded with Cu(I) is due to the interaction of π-complexation between Cu(I) and carbon monoxide. Cu(I) is stabilized strongly at the bridge site and top site of the cluster surfaces. One Cu(I) can adsorb one or two carbon monoxide molecules, with adsorption energy from 50 to 60 kJ/mol, which is much greater than the physical adsorption energy (9.15 kJ/mol) of carbon monoxide on activated carbon. Such energies are both in agreement with available experimental data. DFT is validated as a reliable approach to explain the adsorption of carbon monoxide on activated carbon loaded with Cu(I), which supplies a theoretical basis for the further studies on activated carbon loaded with cuprous salt.