Engineering Pt in Ceria for a Maximum Metal−Support Interaction in Catalysis

Abstract

Conventional supported metal catalysts are metal nanoparticles deposited on high surface area oxide supports with a poorly defined metal−support interface. Typically, the traditionally prepared Pt/ceria catalyzes both methanation (H₂/CO to CH₄) and water−gas shift (CO/H₂O to CO₂/H₂) reactions. By using simple nanochemistry techniques, we show for the first time that Pt or PtAu metal can be created inside each CeO₂ particle with tailored dimensions. The encapsulated metal is shown to interact with the thin CeO₂ overlayer in each single particle in an optimum geometry to create a unique interface, giving high activity and excellent selectivity for the water−gas shift reaction, but is totally inert for methanation. Thus, this work clearly demonstrates the significance of nanoengineering of a single catalyst particle by a bottom-up construction approach in modern catalyst design which could enable exploitation of catalyst site differentiation, leading to new catalytic properties.