Reaction layer thickness of a catalytic mechanism under transient and stationary chronopotentiometric conditions

Molina, Á.; González, Joaquı́n; Soto, Carmen M.

doi:10.1016/j.jelechem.2011.01.020

Cited by 3 publications

(2 citation statements)

References 21 publications

(52 reference statements)

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“…13 Such formulation of M-NP lability is mandatory for e.g. a proper evaluation of the bioavailability of metal ions to organisms in the presence of complexants, 19 for interpreting measurements obtained by dynamic metal speciation techniques such as various voltammetries [20][21][22] and Diffusive Gradients in Thin Films (DGT), [23][24][25] as well as in predicting release kinetics in the context of nanodrug formulations. 7 At the labile limit, complexation of metal ions by nanoparticulate ligands is at equilibrium for any position from the sensing surface so that the overall flux of metal to the sensor results from the coupled diffusion-controlled transport of M-NP and free M. 13 In the other limit of non-labile complexes, the complexation equilibrium 4 is not maintained and the relevant metal flux to the sensor is governed by the rate at which metal ions are released from the particle body.…”

Section: Introductionmentioning

confidence: 99%

“…The lability parameter is a measure of the extent to which the dissociation of the complexes contributes to the flux of metal ions toward the reactive sensing interface . Such formulation of M–NP lability is mandatory for a proper evaluation of the bioavailability of metal ions to organisms in the presence of complexants, for interpreting measurements obtained by dynamic metal speciation techniques such as various voltammetries − and diffusive gradients in thin films, − as well as in predicting release kinetics in the context of nanodrug formulations . At the labile limit, complexation of metal ions by nanoparticulate ligands is at equilibrium for any position from the sensing surface so that the overall flux of the metal to the sensor results from the coupled diffusion-controlled transport of M–NP and free M .…”

Section: Introductionmentioning

confidence: 99%

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Lability of Nanoparticulate Metal Complexes at a Macroscopic Metal Responsive (Bio)interface: Expression and Asymptotic Scaling Laws

2018

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The lability of metal complexes expresses the extent of the dissociative contribution of the complex species to the flux of metal ions toward a macroscopic metal-responsive (bio)interface, e.g. an electrodic sensor or an organism. While the case of molecular ligands is well established, it is only recently that a definition was elaborated for the lability of metal complexes with nanoparticles (NPs) in aqueous dispersions. The definition includes the thickness of the non-equilibrium reaction layer operational at the (bio)interface and the extent of geometrical exclusion of NPs therefrom. In this work, an explicit expression is derived for the lability of nanoparticulate metal complexes (M-NP) towards a macroscopic reactive (bio)interface. Interpretation accounts for the M-NP chemodynamic properties that depend on NP size, electrostatics, metal diffusion and dehydration rates, and density of metal binding sites for various NPs types, i.e. soft/core-shell and hard NPs having volume and surface sites distribution, respectively.Computational examples under practical conditions illustrate how these factors jointly determine the remarkable non-monotonous dependence of M-NP lability parameter on NP size. The analysis is supported by the formulation of asymptotic scaling laws clarifying how local M-NP dissociation dynamics affect the lability parameter for M-NP complexes at the scale of the macroscopic (bio)interface.

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