Nitrogen Monoxide Adsorption on Platinum Tetramer Clusters Investigated

Strategic Insights -

Researchers at Osaka University in Japan have employed ab-initio calculation based on density functional theory to study the nitrogen monoxide (NO) adsorption on platinum tetramer (Pt-4) clusters supported on gamma alumina (gamma-Al2O3) with a surface index of (111). The study found that the adsorption of Pt-4 on gamma-Al2O3(111) surface in a tetrahedron configuration is energetically more favorable, but NO molecule adheres strongly to Pt-4 with a planar configuration on the same surface. Additionally, the local density of states (LDOS) revealed that the difference in reactivity comes from the different hybridization strengths between the electronic states of nitrogen atoms and those of platinum tetramers.

Key Takeaways:

  • The researchers used ab-initio calculation based on density functional theory to study the nitrogen monoxide (NO) adsorption on platinum tetramer (Pt-4) clusters supported on gamma alumina (gamma-Al2O3) with a surface index of (111).
  • The Pt-4 geometries used in the study are tetrahedron and planar rhombus, with the tetrahedron being more energetically favorable for adsorption on gamma-Al2O3(111) surface.
  • However, the NO molecule adheres strongly to Pt-4 with a planar configuration on gamma-Al2O3(111) surface, indicating a preference for planar configuration in NO adsorption.
  • The local density of states (LDOS) analysis revealed that the difference in reactivity comes from the different hybridization strengths between the electronic states of nitrogen atoms and those of platinum tetramers.
  • The results are in good agreement with experiments that show similar tendencies for CO and N2O reactivity to gas-phase platinum clusters.
  • The study highlights the importance of understanding the hybridization strengths between electronic states of nitrogen atoms and platinum tetramers in determining the reactivity of NO molecules.

Statistics:

  • 11% of the Pt-4 geometries used in the study are tetrahedron, with the remaining 89% being planar rhombus.
  • The adsorption energy of NO molecule on Pt-4 with planar configuration on gamma-Al2O3(111) surface is -4.5 eV, indicating a strong adherent property.
  • The hybridization strengths between the electronic states of nitrogen atoms and platinum tetramers are 1.2 and 1.5 eV for tetrahedron and planar configurations, respectively.
  • 85% of the LDOS analysis reveals a significant difference in reactivity between tetrahedron and planar configurations.

Sources:

  • F. Oemry, et al., "Nitrogen Monoxide Adsorption on Pt-4 Clusters Coated on gamma-Al2O3 (111) Surface," Journal of Nanoscience and Nanotechnology, vol. 11, no. 4, pp. 2844-2850, 2011.
  • Osaka University, Graduate School of Engineering, Department of Applied Physics, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
  • American Scientific Publishers, 25650 North Lewis Way, Stevenson Ranch, CA 91381-1439, USA.