Electron transfer processes on Au nanoclusters supported on graphite

Electron transfer processes play an important role in surface chemistry. This paper presents results of a study of changes in resonant electron transfer processes, as a function of gold cluster sizes, on the example of electron transfer between Li + ions scattered on Au clusters on highly oriented pyrolytic graphite (HOPG). The gold nanoclusters were grown on lightly sputtered HOPG surface in order to obtain a wide coverage distribution of clusters. The growth of clusters was monitored by scanning tunneling microscopy. We found that electron transfer is much more probable on small clusters, whose lateral size is of the order of 2 to 3 nm and height in the 1-nm range, than on bulk Au or thin Au films. A comparison with Au clusters grown on the semiconducting titania did not reveal significant differences with HOPG.