Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

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• 作者：Minkyung Kang ; David Perry ; Yang-Rae Kim ; Alex W. Colburn ; Robert A. Lazenby ; Patrick R. Unwin
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：September 2, 2015
• 年：2015
• 卷：137
• 期：34
• 页码：10902-10905
• 全文大小：305K
• ISSN：1520-5126

文摘

There is considerable interest in understanding the interaction and activity of single entities, such as (electro)catalytic nanoparticles (NPs), with (electrode) surfaces. Through the use of a high bandwidth, high signal/noise measurement system, NP impacts on an electrode surface are detected and analyzed in unprecedented detail, revealing considerable new mechanistic information on the process. Taking the electrocatalytic oxidation of H₂O₂ at ruthenium oxide (RuO_x) NPs as an example, the rise time of current鈥搕ime transients for NP impacts is consistent with a hydrodynamic trapping model for the arrival of a NP with a distance-dependent NP diffusion-coefficient. NP release from the electrode appears to be aided by propulsion from the electrocatalytic reaction at the NP. High-frequency NP impacts, orders of magnitude larger than can be accounted for by a single pass diffusive flux of NPs, are observed that indicate the repetitive trapping and release of an individual NP that has not been previously recognized. The experiments and models described could readily be applied to other systems and serve as a powerful platform for detailed analysis of NP impacts.