Control of Metal Nanocrystal Size Reveals Metal-Support Interface Role for Ceria Catalysts

Abstract

Interactions between ceria (CeO2) and supported metals greatly enhance rates for a number of important reactions. However, direct relationships between structure and function in these catalysts have been difficult to extract because the samples studied either were heterogeneous or were model systems dissimilar to working catalysts. We report rate measurements on samples in which the length of the ceria-metal interface was tailored by the use of monodisperse nickel, palladium, and platinum nanocrystals. We found that carbon monoxide oxidation in ceria-based catalysts is greatly enhanced at the ceria-metal interface sites for a range of group VIII metal catalysts, clarifying the pivotal role played by the support.

Solar-Powered Plasmon-Enhanced Heterogeneous Catalysis

“…Defective sites, due to unsaturated chemical bonds, present local extra charge and partial structural rearrangement that favor the adsorption of small molecules in their vicinity if compared with stoichiometric surface regions. In addition, in metal NPs supported on oxides, the interface clearly plays a critical role providing enhanced reactivity [57]. With synchrotronbased x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering spectroscopy (RIXS), some of us recently provided atomistic insights into the electronic and structural localization of plasmon-generated charges in TiO 2 /Au ( Figure 2B).…”

Controlling activity and selectivity using water in the Au-catalysed preferential oxidation of CO in H2

“…More-specific mechanistic PROX investigations by Widmann et al showed that H 2 promotes CO oxidation over Au and the same activated oxygen species is involved in both H 2 and CO oxidation 35 . There is a fairly clear consensus that, for low-temperature CO oxidation, the metal-support interface plays a critical role in the catalysis 11,30,[35][36][37][38] .…”

An extra layer of complexity

“…This is an exciting new development as it suggests potential new routes for modifying the surface chemistry of supported metal nanoparticles. It also highlights the strong influence that adsorbates and the metal-support interface can have on the catalytic chemistry of metal nanoparticles 7,8 .…”