A Comparison of the Adsorption and Diffusion of Hydrogen on the {111} Surfaces of Ni, Pd, and Pt from Density Functional Theory Calculations
A Comparison of the Adsorption and Diffusion of Hydrogen on the {111} Surfaces of Ni, Pd, and Pt from Density Functional Theory Calculations
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DOI：
10.1021/jp002864c
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发表时间：
2001-05
影响因子：
3.3
通讯作者：
G. Watson;R. Wells;D. Willock;G. Hutchings
中科院分区：
文献类型：
--
作者：
G. Watson;R. Wells;D. Willock;G. Hutchings
我们用梯度修正密度泛函理论计算了氢在Ni、Pd和Pt的{111}面上的吸附和热激活扩散路径。我们发现，三种金属的吸附能随吸附位置的变化表现出很大的差异。对于Ni和Pd，吸附能随氢配位的变化而变化，其中3重空心位最稳定，1重空心位稳定性较差。在铂上，所有位置的吸附能都是相似的，这表明在铂上的扩散比在镍或钯上的扩散要快。计算了铂的扩散活化能(2−)，远小于镍和钯的扩散活化能(13kJ·mol-1)。计算得到的吸附和活化能与实验研究的结构、能量和扩散性质符合得很好。
We present gradient corrected density function theory calculations on the adsorption and thermally activated diffusion pathways of hydrogen on the {111} surfaces of Ni, Pd, and Pt. We find that the variation of the adsorption energy as a function of adsorption site shows considerable differences between the three metals. For Ni and Pd, the adsorption energies vary as a function of hydrogen coordination with the 3-fold hollow sites the most stable and the 1-fold atop site considerably less stable. On Pt the adsorption energies for all the sites are similar indicating that diffusion across the surface will be faster on Pt than on Ni or Pd. The activation energies for diffusion have been calculated with that for Pt (2−3 kJ mol-1) considerably smaller than for Ni or Pd (13 kJ mol-1). The calculated adsorption and activation energies are in good agreement with experimental investigations of the structure, energetics, and diffusion properties.