Nanoscale Kirkendall Effect and Oxidation Kinetics in Copper Nanocrystals Characterized by Real‐Time, In Situ Optical Spectroscopy. (5th September 2014)

• Record Type: Journal Article
• Authors: Rice, Katherine P.; Paterson, Andrew S.; Stoykovich, Mark P.
• Is Part Of: Particle and particle systems characterization. Volume 32:Number 3(2015:Mar.)
• Page Start: 373
• Page End: 380
• Publication Date: 2014-09-05
• Subjects: Particles -- Periodicals; 620.43
• DOI: 10.1002/ppsc.201400155
• Languages: English
• ISSNs: 0934-0866

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The low‐temperature oxidation of ≈10 nm diameter copper nanocrystals is characterized using in situ UV–vis absorbance spectroscopy and observed to lead to hollow copper oxide shells. The kinetics of the oxidation of solid Cu nanocrystals to hollow Cu₂O nanoparticles is monitored in real‐time via the localized surface plasmon resonance response of the copper. A reaction‐diffusion model for the formation of hollow nanoparticles is fit to the measured time for complete Cu nanocrystal oxidation, and is used to quantify the diffusion coefficient of Cu in Cu₂O and the activation energy of the oxidation process. The diffusivity measured here in single‐crystalline nanoscale systems is 1–5 orders of magnitude greater than in comparable systems in the bulk, and have an Arrhenius dependence on temperature with an activation energy for diffusion of 37.5 kJ mol⁻¹ for 85 °C ≤ <italic>T</italic> ≤ 205 °C. These diffusion parameters are measured in some of the smallest metal systems and at the lowest oxidation temperatures yet reported, and are enabled by the unique nanoscale single‐crystalline material and the in situ characterization technique.</p> </abstract>