  Direct real time studies of reacting individual atoms in technologically
important gold and platinum nanocatalysts in controlled reducing and oxidising
gas environments and operating temperatures using novel environmental scanning
transmission electron microscopy (ESTEM) with single atom sensitivity are
presented. The direct in situ observations provide new insights into the
dynamic behaviour of single atoms which may be important as catalytic active
sites as well as migrating as part of deactivation mechanisms. The single atom
dynamics reveal that the primary role of nanoparticles in the catalysts is to
act as reservoir of ad-atoms or clusters. Possible reaction mechanisms are
described briefly
