Copper catalysis at operando conditions—bridging the gap between single nanoparticle probing and catalyst-bed-averaging

Abstract

In catalysis, nanoparticles enable chemical transformations and their structural and chemical fingerprints control activity. To develop understanding of such fingerprints, methods studying catalysts at realistic conditions have proven instrumental. Normally, these methods either probe the catalyst bed with low spatial resolution, thereby averaging out single particle characteristics, or probe an extremely small fraction only, thereby effectively ignoring most of the catalyst. Here, we bridge the gap between these two extremes by introducing highly multiplexed single particle plasmonic nanoimaging of model catalyst beds comprising 1000 nanoparticles, which are integrated in a nanoreactor platform that enables online mass spectroscopy activity measurements. Using the example of CO oxidation over Cu, we reveal how highly local spatial variations in catalyst state dynamics are responsible for contradicting information about catalyst active phase found in the literature, and identify that both surface and bulk oxidation state of a Cu nanoparticle catalyst dynamically mediate its activity.

Grain-growth mediated hydrogen sorption kinetics and compensation effect in single Pd nanoparticles

“…For all experiments, they are used starting in the freshly grown state, without any prior annealing. To resolve the fast hydrogen sorption kinetics for all single particles simultaneously, we have employed multiplexed single-particle plasmonic nanoimaging microscopy 34 , in which optical contrast is generated by measuring changes in spectrally integrated scattering intensity. Accordingly, we rely on the linear optical contrast between neat Pd, Pd-H in the solid solution α-phase, in the α+β coexistence region, and in the pure β-phase (hydride) 35 , 36 .…”

Shedding Light on CO Oxidation Surface Chemistry on Single Pt Catalyst Nanoparticles Inside a Nanofluidic Model Pore

“… 22 Finally, we highlight that single-particle plasmonic nanoimaging can be used to investigate large numbers of individual nanoparticles in parallel, which makes optical characterization of the whole catalyst bed possible, while activity measurements from the same bed become readily available in combination with nanofluidic reactors. 27 Therefore, we propose the development of transmission electron microscopy-compatible nanoreactors to enable measurements of single-particle structure–function correlations within a catalyst bed that is large enough to enable statistical analysis of hundreds to thousands of individual particles measured simultaneously, to thereby minimize measurement-to-measurement artifacts and ensure that the averaged single-particle response reproduces the response of the whole catalyst bed.…”

Dynamics of Heterogeneous Catalytic Processes at Operando Conditions

“…For the CO oxidation that uses nanoparticles, Albinsson et al. 192 pointed out the importance of bridging the gap between local and averaging characterization methods. With operando plasmonic nanoimaging, they revealed that both surface and bulk oxidation states changed by the CO oxidation of a Cu catalyst.…”