Anomalous behavior of atomic hydrogen interacting with gold clusters

Area of Science:

• Physical Chemistry
• Materials Science
• Surface Science

Background:

• Gold clusters exhibit unique catalytic properties.
• The electronic structure of hydrogen in metallic systems is typically anionic or covalent.
• Understanding hydrogen's interaction with gold clusters is key to explaining their catalytic behavior.

Purpose of the Study:

• To investigate the electronic structure changes in gold clusters upon hydrogen atom substitution.
• To elucidate the interaction mechanism between hydrogen and gold anion clusters.

Main Methods:

• Photoelectron spectroscopy was employed to study gold anion clusters (Au(n)-).
• Clusters were reacted with individual hydrogen atoms and molecular hydrogen.

Main Results:

• Gold anion clusters react with single hydrogen atoms but not molecular hydrogen.
• Spectra of Au(n)- and Au(n-1)H- clusters (for n > 2) showed nearly identical features.
• Hydrogen contributes one electron to the gold cluster's valence pool, behaving as a proton.

Conclusions:

• Hydrogen exhibits unusual protonated behavior in gold clusters, contrasting with its typical anionic or covalent form in bulk metals.
• This unique electronic interaction influences the catalytic activity of gold clusters.