Metal-insulator transition-induced adsorption-resistant behavior of small Au nanoparticles.

Smaller nonmetallic nanoparticles are more inert: Metal-insulator transition of Au nanoparticles on silica is closely related to the metal-support charge transfer, which has a strong influence on chemisorption reactivity of Au. Smaller nonmetallic Au nanoparticles are more resistant towards butanethiol chemisorption [picture and graph: see text].The size-dependent variation of the electronic and chemical properties of Au nanoparticles formed on native Si oxide surfaces is investigated using synchrotron radiation photoemission spectroscopy and ultraviolet photoelectron spectroscopy.