Improved NO–CO reactivity of highly dispersed Pt particles on CeO2 nanorod catalysts prepared by atomic layer deposition

Abstract

Highly dispersed platinum (Pt) nanoparticles are deposited on CeO₂ nanorods via atomic layer deposition (ALD) to improve the catalytic activity towards the NO–CO reaction. For comparison, CeO₂ nanosphere and CeO₂ nanorod loaded Pt nanoparticle catalysts fabricated by ALD and incipient wetness impregnation (IWI) are studied. The size distribution of Pt nanoparticles of Pt/CeO₂ nanosphere (Pt/CeO₂-NS) and Pt/CeO₂ nanorod (Pt/CeO₂-NR) catalysts prepared by ALD is quite narrow and uniform (3.05 ± 0.42 nm for Pt/CeO₂-NSs, and 3.05 ± 0.38 nm for Pt/CeO₂-NRs) compared to that of the Pt_IWI/CeO₂-NS catalyst prepared by incipient wetness impregnation. The combination of XPS, H₂-TPR, XAFS and in situ DRIFTS characterization techniques confirms that the strong interaction between Pt nanoparticles and CeO₂ nanorods leads to the decrease of the CO poisoning effect on Pt and activation of oxygen around the interfaces. As a result, the full conversion of NO takes place at a relatively low temperature of ∼200 °C, revealing that the activity of the ALD prepared Pt/CeO₂-NR catalyst is greatly enhanced.