Nitrogen monoxide adsorption on Pt4 clusters coated on gamma-Al2O3 (111) surface

Area of Science:

• Surface Science
• Computational Chemistry
• Materials Science

Background:

• Platinum (Pt) clusters are crucial catalysts.
• Understanding their interaction with support materials like gamma alumina (gamma-Al2O3) is vital for catalyst design.
• Nitrogen monoxide (NO) is a common pollutant and a probe molecule in catalysis.

Purpose of the Study:

• To investigate the adsorption behavior of nitrogen monoxide (NO) on platinum tetramer (Pt4) clusters supported on the gamma-Al2O3 (111) surface.
• To compare the adsorption energies and electronic properties of NO on different Pt4 cluster configurations (tetrahedron vs. planar rhombus).
• To elucidate the underlying electronic factors governing the NO-Pt4 interaction.

Main Methods:

• Ab-initio calculations based on density functional theory (DFT).
• Investigation of Pt4 cluster geometries: tetrahedron and planar rhombus.
• Analysis of adsorption energies and local density of states (LDOS).

Main Results:

• The tetrahedral Pt4 configuration is energetically more favorable for adsorption on the gamma-Al2O3 (111) surface.
• However, NO molecules exhibit stronger adhesion to the planar rhombus Pt4 configuration.
• This preference for the planar configuration was also observed for isolated Pt4 clusters and is attributed to differences in electronic hybridization.

Conclusions:

• The adsorption geometry of the platinum tetramer cluster significantly influences the binding strength of nitrogen monoxide.
• Electronic structure differences, specifically hybridization between nitrogen and platinum atoms, dictate the reactivity.
• These findings align with experimental observations for similar systems, validating the computational approach.