On the catalytic activity of palladium clusters generated with the electrochemical scanning tunnelling microscope

摘要

Recent experiments have shown that small palladium clusters, deposited on Au(111) with a scanning tunnelling microscope, are better catalysts for the hydrogen evolution reaction than larger clusters, and may even be more active than bulk palladium. We suggest that the larger clusters contain an admixture of gold, which lowers the density of states at the Fermi level. In addition, there is charge transfer from the gold to the palladium, which induces a high electric field at the surfaces of small clusters, which favours hydrogen evolution.