title: Real time observation of chemical reactions of individual metal nanoparticles with high-throughput single molecule spectral microscopy.
abstract: Real time observation of chemical reactions of individual noble metal nanoparticles (MNPs) is fundamentally important to their controlled synthesis, chemical sensing and catalysis applications. Here, with a simple and high-throughput single-molecule darkfield spectral imaging technique, we demonstrate that the reaction-induced plasmonic resonance variations of multiple MNPs could be monitored in parallel. Oxidation kinetics of individual gold nanorods (AuNRs), either immobilized on a glass substrate or moving freely in homogeneous solution, was recorded successfully. Heterogeneous reaction pathways and intermediate states unobservable in ensemble UV-visible measurements were revealed. Interestingly, the oxidation rate of individual immobilized AuNRs was much slower than that of the bulk AuNR solution, which implies the existence of a novel self-catalysis mechanism. This high-throughput darkfield spectral imaging technique could be applied to chemical reaction kinetics and heterogeneous catalysis studies of other MNPs at single particle level.
authors.affiliation: Biomedical Engineering Center, College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Cheng
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Cheng
authors.forename: Yan
authors.initials: Y
authors.lastname: He
authors.forename: Edward S
authors.initials: ES
authors.lastname: Yeung
mesh_terms: D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008853:Microscopy / Q000379:methods*; D010084:Oxidation-Reduction; D013997:Time Factors