Adsorbate-induced structural evolution changes the mechanism of CO oxidation on a Rh/Fe3O4(001) model catalyst.
Zdeněk JakubJan HulvaPaul T P RyanDavid A DuncanDavid J PayneRoland BliemManuel UlreichPatrick HofeggerFlorian KraushoferMatthias MeierMichael SchmidUlrike DieboldGareth S ParkinsonPublished in: Nanoscale (2020)
The structure of a catalyst often changes in reactive environments, and following the structural evolution is crucial for the identification of the catalyst's active phase and reaction mechanism. Here we present an atomic-scale study of CO oxidation on a model Rh/Fe3O4(001) "single-atom" catalyst, which has a very different evolution depending on which of the two reactants, O2 or CO, is adsorbed first. Using temperature-programmed desorption (TPD) combined with scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), we show that O2 destabilizes Rh atoms, leading to the formation of RhxOy clusters; these catalyze CO oxidation via a Langmuir-Hinshelwood mechanism at temperatures as low as 200 K. If CO adsorbs first, the system is poisoned for direct interaction with O2, and CO oxidation is dominated by a Mars-van-Krevelen pathway at 480 K.
Keyphrases
- visible light
- room temperature
- high resolution
- ionic liquid
- reduced graphene oxide
- highly efficient
- electron transfer
- hydrogen peroxide
- metal organic framework
- carbon dioxide
- single molecule
- electron microscopy
- molecular dynamics
- diabetic rats
- drug induced
- optical coherence tomography
- mass spectrometry
- high throughput
- stress induced
- endothelial cells