PHYS 14 |
| Metal nanoparticles are important catalysts for many chemical transformations. However, due to their morphology dispersions and variable surface active sites, nanoparticles have heterogeneous catalytic activities that are challenging to characterize in ensemble measurements. Using a single-nanoparticle approach, we monitor redox catalytic turnovers of Au-nanoparticles in solution in real time via single-molecule detection of fluorescent products. We found the catalysis occurs via a Langmuir-Hinshelwood mechanism and the product formation and dissociation occur at different surface sites. Monodisperse Au-nanoparticles display large static activity heterogeneity; and the activity of individual nanoparticles fluctuates, attributable to catalysis-induced and spontaneous dynamic surface restructuring at a timescale of about 10-100 seconds. Our results highlight the power of the single-nanoparticle single-turnover approach in revealing the interplay of catalysis, heterogeneous sites, and surface structural dynamics in nanocatalysis. |
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Nanostructured Materials
8:10 AM-12:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 338/339, Oral
Division of Physical Chemistry |