Size- and Shape-Sensitive Reactivity Behavior of Al-n(n=2-5, 13, 30, and 100) Clusters Toward the N-2 Molecule: A First-Principles Investigation

作者：Kulkarni Bhakti S; Krishnamurty Sailaja; Pal Sourav^*

来源：Journal of Physical Chemistry C, 2011, 115(30): 14615-14623.

DOI：10.1021/jp203452a

Reactivity of aluminum clusters has been found to exhibit size-sensitive variations. N-2 reduction is a hard process, and its dissociation on the Al surface is one of the few chemical methods available under nonhazardous conditions. In this context, we attempt to understand the adsorption behavior of N-2 molecules as a function of varying size and shape of Al clusters using a Density Functional Theory (DFT) based method. During the complex formation, various N-2 adsorption modes are examined. The results clearly demonstrate that, while the interaction energy does not vary with respect to the cluster size, shape of the cluster is highly contributive toward the chemisorption (a prerequisite for the reactivity) of the N-2 molecule. The underlying electronic and structural factors influencing the adsorption of N-2 molecules on the Al clusters are analyzed with the help of the Electron Localization ELF) and Frontier Molecular Orbitals. As an illustration, the activation barrier calculations on various Al-13 conformations are calculated, and results confirm the experimental propositions that high-energy structures (depending upon their geometrical and electronic orientation) are more favorable for N-2 reduction.

• 出版日期2011-8-4