Single?Site vs. Cluster Catalysis in High Temperature Oxidations

The behavior of single Pt atoms and small clusters was investigated for high-temperature oxidations. high stability these molecular sites in CHA is a key to intrinsic structure-performance descriptions elemental steps such as O2 dissociation, subsequent oxidation catalysis. Subtle changes the atomic structure are responsible drastic performance driven by specific gas/metal/support interactions. Whereas (> ca. 1?nm) unable activate, scramble, desorb two molecules at moderate T (200?°C), <1?nm do so catalytically, but undergo oxidative fragmentation. Oxidation alkanes attributed stable atoms, C-H cleavage inferred be rate-determining less sensitive metal nuclearity compared its effect on scrambling. In contrast, when combustion involves CO, catalysis dominated clusters, not atoms.