The nucleation, growth, and stability of oxide-supported metal clusters

The optimization of oxide-supported metal clusters as heterogeneous catalysts requires a detailed understanding of the metal cluster–oxide interface. Model catalysts, prepared by deposition of a catalytically active metal onto a thin film oxide support, closely mimic real-world catalysts, yet are amenable to study using surface sensitive techniques. Surface science methods applied to model catalysts, combined with the use of in situ high-pressure reaction studies, have provided a wealth of information about cluster structure and reactivity. STM capabilities for imaging individual particles under reaction temperatures and pressures offer a new approach for studying supported cluster catalysts on a particle-by-particle basis. This article describes recent work in our laboratories using variable temperature STM to investigate the role of the support and its defects in the nucleation and stabilization of metal clusters.