Nanofluidics is related to controlling fluids on length scales &lt; 100 nm inside tiny channels fabricated into a flat support. Decorating such nanochannels with catalytic nanoparticles therefore constitutes a new paradigm for studying catalytic reactions, where the mass transport to and from single nanoparticles can be accurately controlled without excessive dilution of the formed products. This, in turn, enables their quantitative analysis using both optical methods and quadrupole mass spectrometry. In combination with optical nanoimaging techniques that reveal the catalyst state, this concept thus provides ample opportunities for establishing structure-function correlations at the single nanoparticle level, as well as for the imaging of an entire model catalyst bed with single particle resolution to reveal effects of local conversion and mass transport gradients. In this talk, I will introduce this concept of single particle catalysis in nanofluidic reactors that we have established recently,1-3 and outline its potential on a number of specific examples. They include CO oxidation over single Cu nanoparticles in a nanofluidic model pore2 and in a model catalyst bed comprising 1000 Cu nanoparticles,4 where the former explicitly visualizes reactant concentration gradient formation due to conversion on single nanoparticles, and the latter reveals how dynamic spatial variations in catalyst state may be responsible for contradicting information about the active catalyst phase. Furthermore, I will discuss how the trapping of individual colloidal nanocrystals inside nanofluidic channels opens the door to revealing structure-activity correlations at the individual nanoparticle level, and how machine learning combined with nanofluidic reactors pushes the limits of the required amount of catalyst material in online quadrupole mass spectroscopic detection.

Combining nanofluidics with nanoimaging and mass spectrometry for single particle catalysis

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.