A facet-selective atomic layer deposition method is developed to fabricate oxide nanofence structure to stabilize Pt nanoparticles. CeO is selectively deposited on Pt nanoparticles' (111) facets and naturally exposes Pt (100) facets. The facet selectivity is realized through different binding energies of Ce precursor fragments chemisorbed on Pt (111) and Pt (100), which is supported by in situ mass gain experiment and corroborated by density functional theory simulations. Such nanofence structure not only has exposed Pt active facets for carbon monoxide oxidation but also forms ceria-metal interfaces that are beneficial for activity enhancement. The composite catalysts show excellent sintering resistance up to 700 °C calcination. CeO anchors Pt nanoparticles with a strong metal oxide interaction, and nanofence structure around Pt nanoparticles provides physical blocking that suppresses particles migration. The study reveals that forming oxide nanofence structure to encapsulate precious metal nanoparticles is an effective way to simultaneously enhance catalytic activity and thermal stability.

No abstract

A selective atomic-layer-deposition method is developed to decorate platinum (Pt) nanoparticles (NPs) with nickel oxides (NiO x ), resulting in greatly improved catalytic performance. During the initial growth stage, NiO x can be selectively deposited on the low coordinated sites of Pt NPs. Selectivity is realized through intrinsic binding energy differences of nickel (Ni) precursor on Pt sites, which has been confirmed by Fourier transform infrared characterizations and density functional theory simulations. The NiO x /Pt/Al 2 O 3 catalysts show enhanced activity toward CO oxidation, which is mainly due to the highly active metal oxide interfaces created. More importantly, the sintering resistance of the composite NiO x /Pt/Al 2 O 3 catalysts has been improved significantly, which can be attributed to the stabilization of volatile atoms at low coordinated sites and the strong metal oxide interaction that anchors Pt NPs. This study reveals that selective passivation is an effective method to simultaneously enhance the catalytic activity and stability.

No abstract

No abstract