title: Spatiotemporal catalytic dynamics within single nanocatalysts revealed by single-molecule microscopy.
abstract: This review discusses the latest advances in using single-molecule microscopy of fluorogenic reactions to examine and understand the spatiotemporal catalytic behaviors of single metal nanoparticles of various shapes including pseudospheres, nanorods, and nanoplates. Real-time single-turnover kinetics reveal size-, catalysis-, and metal-dependent temporal activity fluctuations of single pseudospherical nanoparticles (<20 nm in diameter). These temporal catalytic dynamics can be related to nanoparticles' dynamic surface restructuring whose timescales and energetics can be quantified. Single-molecule super-resolution catalysis imaging further enables the direct quantification of catalytic activities at different surface sites (i.e., ends vs. sides, or corner, edge vs. facet regions) on single pseudo 1-D and 2-D nanocrystals, and uncovers linear and radial activity gradients within the same surface facets. These spatial activity patterns within single nanocrystals can be attributed to the inhomogeneous distributions of low-coordination surface sites, including corner, edge, and defect sites, among which the distribution of defect sites is correlated with the nanocrystals' morphology and growth mechanisms. A brief discussion is given on the extension of the single-molecule imaging approach to catalysis that does not involve fluorescent molecules.
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14854, USA. pc252@cornell.edu.
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Zhou
authors.forename: Nesha May
authors.initials: NM
authors.lastname: Andoy
authors.forename: Kyu-Sung
authors.initials: KS
authors.lastname: Han
authors.forename: Eric
authors.initials: E
authors.lastname: Choudhary
authors.forename: Ningmu
authors.initials: N
authors.lastname: Zou
authors.forename: Guanqun
authors.initials: G
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Shen