(670f) Single-Molecule Imaging of Nanoscale Catalysis

Metal nanoparticles and carbon nanotubes are used in a variety of catalytic systems for energy conversion and production, including photoelectrochemical cells, fuel cells, and batteries. Understanding their structure and catalytic properties is essential for improving their performance and integrating them in devices for applications. Although their structures can be studied down to atomic resolution, their catalytic activities have been mainly studied at the ensemble level, obtaining averaged properties. Ensemble-averaged study is fundamentally inadequate for nanoparticles and carbon nanotubes, however, as they are intrinsically heterogeneous -- Nanoparticles have structural dispersions and carbon nanotubes have various chirality. Here I report our efforts in using single-molecule fluorescence imaging to study the catalytic properties of metal nanoparticles and single-walled carbon nanotubes (SWNTs) at the single-particle/single-tube level. Specifically, I will describe (1) imaging catalysis of individual metal nanoparticles at the single-particle single-turnover resolution in real time under ambient conditions, and (2) imaging electrocatalysis of SWNTs at the single reactive site, single-turnover resolution.