Non-invasive probing of nanoparticle electrostatics

Tschulik, Kristina; Cheng, Wei; Batchelor-McAuley, Christopher; Murphy, Stuart; Omanović, Dario; Compton, Richard (2015) Non-invasive probing of nanoparticle electrostatics. ChemElectroChem, 2 (1). pp. 112-118. ISSN 2196-0216

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Abstract

Electrostatic interactions between surface- charged nanoparticles (NPs) and electrodes studied using existing techniques unavoidably and significantly alter the system being analyzed. Here we present a methodology that allows the probing of unperturbed electrostatic interactions between individual NPs and charged surfaces. The uniqueness of this approach is that stochastic NP impact events are used as the probe. During a single impact, only an attomole of the redox species reacts and is released at the interface during each sensing event. As an example, the effect of electrostatic screening on the reduction of negatively charged indigo NPs at a mercury microelectrode is explored at potentials positive and negative of the potential of zero charge. At suitable overpotentials fully driven electron transfer is seen for all but very low (<0.005 m) ionic strengths. The loss of charge transfer in such dilute electrolytes is unambiguously shown to arise from a reduced driving force for the reaction rather than a reduced population of NPs near the electrode, contradicting popular perceptions. Electrostatics were found not to significantly affect the reactivity of the studied NPs. Importantly, the presented technique is general and can be applied to a wide variety of NPs, including metals, metal oxides and organic compounds.

Item Type:	Article
Uncontrolled Keywords:	Coulomb interactions; electron transfer; electrostatic repulsion; organic nanoparticles; single nanoparticle impacts
Subjects:	NATURAL SCIENCES > Chemistry
Divisions:	Division for Marine and Enviromental Research
Projects:	Project title Project leader Project code Project type Marie Curie Intra European Fellowship within the 7th European Community Framework Programme UNSPECIFIED 327706 UNSPECIFIED European Research Council under the European Union's Seventh Framework Programme (FP)/ERC UNSPECIFIED 320403 UNSPECIFIED Leverhulme Trust UNSPECIFIED F/08 788J UNSPECIFIED
Depositing User:	Dario Omanović
Date Deposited:	19 Dec 2016 17:05
URI:	http://fulir.irb.hr/id/eprint/3223
DOI:	10.1002/celc.201402285

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