Metal nanoparticles dispersed on oxide supports have been widely investigated due to their remarkable reactivity with gases in the field of chemical and electrochemical catalysis. In particular, ceria (CeO2)-supported metals have been known to improve the rate of many reactions due to the vital role of the ceria-metal interfaces considered as a key active site. Here, we quantify the interface effect on the rate of catalytic reactions, particularly in this case CO and CH4 oxidation. Pt@CeO2 core-shell nanoparticles were prepared in different Pt-core sizes with narrow size distribution (e.g., 6.7 ± 0.9 nm, 11 ± 1.5 nm, and 20 ± 1.9 nm) and their activities toward CO and CH4 oxidation were analyzed. Those core-shell configurations allow us not only to control the site density of metal-oxide interfaces, but also to achieve robust thermal stability against sintering, thus enabling precisely to investigate the effect of interfacial site density over the reaction rate. We observed that a linear power law dependence of log rate on particle diameter regardless of exposed metallic surface area, confirming the enhanced ceria-metal interactions with increased interface site densities. This model system with well-defined interface structures may shed new light on understanding unique interfacial phenomena over the highly active, supported metal catalysts.

Control of metal-oxide interfaces for ceria-based nanocatalysts

253rd National Meeting (2017)

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