Tuning the morphology of gold clusters by substrate doping

Area of Science:

• Materials Science
• Surface Science
• Catalysis

Background:

• Small metal cluster morphology significantly influences electronic, magnetic, and chemical properties.
• Planar gold (Au) clusters on magnesium oxide (MgO) substrates are catalytically desirable but typically disfavored over tetrahedral structures.

Purpose of the Study:

• To investigate a practical method for stabilizing planar gold clusters over tetrahedral ones.
• To explore the effect of doping the MgO substrate with aluminum (Al) atoms on gold cluster morphology.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• The energy differences between planar and tetrahedral gold cluster geometries on MgO were analyzed.
• The impact of aluminum dopant concentration and position on cluster stability was assessed.

Main Results:

• Doping MgO with Al atoms stabilizes the planar Au cluster geometry over the tetrahedral one.
• The energy stabilization is linearly proportional to the Al dopant concentration.
• The stabilization effect is independent of the dopant atom's position on the substrate.
• Charge transfer to the gold cluster also shows a monotonic dependence on doping concentration.

Conclusions:

• Aluminum doping of MgO provides a viable strategy to favor planar gold cluster formation.
• This approach has significant implications for advancing gold nanocatalysis.
• The findings offer a tunable method for controlling cluster morphology and properties.