Mesoporous Materials‐Based Electrochemical Sensors

Walcarius, Alain

doi:10.1002/elan.201400628

Cited by 120 publications

(91 citation statements)

References 342 publications

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“…Electrochemistry in small spaces has attracted significant interest because of intriguing effects of the nanoconfinement on electrochemical kinetics, transport, double layer, and solvent properties, as well as a number of promising applications of nanoporous electrodes to sensors and energy conversion and storage . Complicated electrochemical processes involving nano‐confined species remain poorly understood, and nanoporous electrodes are not a good model for studying such processes, because of their intricate structure and electrochemical behavior.…”

Section: Figurementioning

confidence: 99%

Recessed Nanoelectrodes for Nanogap Voltammetry

Bae

Mirkin

2016

ChemElectroChem

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Exploration of electrochemical properties of nanoconfined species is an area of active interest. In this Communication, recessed Pt nanoelectrodes were prepared by controlled electrochemical etching and evaluated by combination of voltammetry and atomic force microscopy. The effects of ac frequency and ac voltage on the etching process are discussed. Voltammetry was carried out in the nanogap between the etched nanoelectrode and the planar substrate surface. Peak‐shaped steady‐state voltammograms were obtained with a low concentration of supporting electrolyte and fitted to the theory, pointing to the influence of the electrical double layer on transport of a charged redox species within the confined space.

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Section: Figurementioning

confidence: 99%

Recessed Nanoelectrodes for Nanogap Voltammetry

Bae

Mirkin

2016

ChemElectroChem

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“…Mesoporous silica thin films on electrodes have recently attracted considerable attention, notably in the field of electrochemical sensors and biosensors as well as energy conversion and storage . The conventional way to generate mesoporous silica thin films on solid supports is the formation of surfactant‐templated silica materials by evaporation‐induced self‐assembly (EISA), and this method has also been successfully applied to the modification of electrode surfaces .…”

Section: Introductionmentioning

confidence: 99%

Amplified Charge Transfer for Anionic Redox Probes through Oriented Mesoporous Silica Thin Films

2016

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Diffusion of anionic species through ordered mesoporous silica films is considerably restricted due to electrostatic repulsion by the negatively charged silica surface and this effect is even worse in low ionic strength media (owing to Donnan exclusion effects). This is at the origin of the poor electrochemical response of anionic redox probes at electrodes modified with such mesoporous thin films. Here, by using indium–tin oxide (ITO) electrodes covered with vertically aligned mesoporous silica films generated by electrochemically assisted self‐assembly (EASA), we show that charge transfer for anionic redox probes [i.e. Fe(CN)63−/4−] can be dramatically amplified by using a neutral [ferrocene dimethanol, Fc(MeOH)2] or cationic [(Ru(NH3)63+] redox mediator. This has been observed by cyclic voltammetry, showing current enhancement in the presence of the mediator, which acts as a mobile electron shuttle between the charge‐excluded Fe(CN)63−/4− species from the mesoporous silica film and the underlying ITO surface owing to the ability of the mediator species to diffuse freely through the oriented mesopore channels. This behavior was significantly affected by the relative contents of Fe(CN)63−/4− probe to Fc(MeOH)2 mediator, the potential scan rate, and the supporting electrolyte concentration. The most effective improvements were reached at low Fe(CN)63−/4− concentration, high mediator content, low potential scan rate, and low ionic strength.

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“…Silica based materials exhibiting high surface areas, good adsorption, and efficient catalytic effect. These remarkable features result in better charge transport and improved electrochemical signal .…”

Section: Resultsmentioning

confidence: 99%

Development of a Sensor Based on Modified Carbon Paste with Com Iron(III) Protoporphyrin Immobilized on SiNbZn Silica Matrix for L‐tryptophan Determination

2017

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In this work, SiO2/Nb2O5/ZnO prepared by the sol‐gel processing method was used as substrate base for immobilization of the protoporphyrin‐IX ion. Iron(III) ion was inserted into the porphyrin ring (SiNbZn‐PPFe). A simple square wave voltammetry method based on a composite sensor carbon paste electrode of this material,designed as EPC‐SiNbZn‐PPFe, was developed and validated successfully for the determination of L‐tryptophan (Trp). The optimum conditions were obtained by using sensor modified with 18.00 mg SiNbZn‐PPFe material, 12.00 mg graphite powder and 6.0 μL mineral oil and phosphate buffer 0.3 mol L−1 pH 7.0. The sensitivity of the sensor was found to be 0.523 AL mol −1, linear range from 10 to 70 μmol L−1 and limit of detection of 3.28 μmol L−1. Therefore, the developed method was successfully applied for the Trp determination in real samples of pharmaceutical formulation and can be used for routine quality control pharmaceutical formulations containing Trp.

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Mesoporous Materials‐Based Electrochemical Sensors

Cited by 120 publications

References 342 publications

Recessed Nanoelectrodes for Nanogap Voltammetry

Recessed Nanoelectrodes for Nanogap Voltammetry

Amplified Charge Transfer for Anionic Redox Probes through Oriented Mesoporous Silica Thin Films

Development of a Sensor Based on Modified Carbon Paste with Com Iron(III) Protoporphyrin Immobilized on SiNbZn Silica Matrix for L‐tryptophan Determination

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