title: In Situ Detection of Particle Aggregation on Electrode Surfaces.
abstract: Partially blocked electrodes (PBEs) are important; many applications use non-conductive nanoparticles (NPs) to introduce new electrode functionalities. As aggregation is a problem in NP immobilization, developing an in situ method to detect aggregation is vital to characterise such modified electrodes. We present chronoamperometry as a method for detection of NP surface aggregation and semi-quantitative sizing of the formed aggregates, based on the diffusion limited current measured at PBEs as compared with the values calculated numerically for different blocking feature sizes. In contrast to voltammetry, no approximations on electrode kinetics are needed, making chronoamperometry a more general and reliable method. Sizing is shown for two modification methods. Upon drop casting, significant aggregation is observed, while it is minimized in electrophoretic NP deposition. The aggregate sizes determined are in semi-quantitative agreement with ex situ microscopic analysis of the PBEs.
authors.affiliation: Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ (United Kingdom).
authors.forename: Kamonwad
authors.initials: K
authors.lastname: Ngamchuea
authors.affiliation: Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ (United Kingdom).
authors.forename: Kristina
authors.initials: K
authors.lastname: Tschulik
authors.affiliation: Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ (United Kingdom).
authors.forename: Shaltiel
authors.initials: S
authors.lastname: Eloul
authors.affiliation: Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ (United Kingdom).. richard.compton@chem.ox.ac.uk.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Compton
keywords: chronoamperometry; electrochemical sizing; non-conductive nanoparticles; numerical simulation; partially blocked electrodes