On the way of understanding the behavior of nanometer-scale metallic particles toward the adsorption of CO and NO molecules

Cu n Clusters (n = 13, 43, and 55) as Possible Degradant Agents of mSF6 Molecules (m = 1, 2): A DFT Study

In order to obtain the structural and electronic properties of pristine copper clusters and Cu₁₃-SF₆, Cu₄₃-SF₆, Cu₅₅-SF₆, Cu₁₃-2SF₆, Cu₄₃-2SF₆, and Cu₅₅-2SF₆ systems, DFT calculations were carried out. For Cu₁₃-mSF₆, its surface suffers a drastic deformation, and Cu₄₃-mSF₆ at its outer surface reveals strong interaction for the first chemical molecule; when the second molecule is interacting, these outer surfaces are not severely affected. These two cases degraded fully the first SF₆ molecule; however the second molecule is bonded to the latter systems and for Cu₅₅-mSF₆ (m = 1 and 2) a structural transformation from SF₆ →SF₄ appears as well as inner and outer shells that display slight deformations. The electronic gaps do not exhibit drastic changes after adsorption of mSF₆ molecules, and the magnetic moment remains without alterations. The whole system shows thermal and vibrational stability. In addition, for Cu₁₃-mSF₆ the values of the optical gap and intensity of the optical exhibit changes with respect to the pristine case (Cu₁₃), and the rest of the systems do not exhibit major oscillations. These icosahedral copper clusters emerge as a good option to degrade mSF₆ molecules.

Synergistic Effects in the Activity of Nano-Transition-Metal Clusters Pt12M (M = Ir, Ru or Rh) for NO Dissociation

The dissociation of environmentally hazardous NO through dissociative adsorption on metallic clusters supported by oxides, is receiving growing attention. Building on previous research on monometallic M 13  clusters [J. Phys. Chem. C, 2019, 123(33), 20314-20318], this work considers bimetallic Pt 12 M (M = Rh, Ru or Ir) clusters. The adsorption energy and activation energy of NO dissociation on the clusters have been calculated in vacuum using Koh,-Sham DFT, while their trends were rationalized using reactivity indices such as molecular electrostatic potential and global Fermi softness. The results shown that doping of the Pt clusters lowered the adsorption energy as well as the activation energy for NO dissociation. Furthermore, reactivity indices were calculated as a first estimate of the performance of the clusters in realistic amorphous silica pores (MCM-41) through  ab initio  molecular dynamics simulations.