T. Bombail, P. Garrigue, B. Goudeau, D. Talaga, L. Bouffier, S. Bonhommeau, L. Servant, D. Zigah, S. Arbault, N. Sojic

Electrochim. Acta, 2019, DOI: 10.1016/j.electacta.2019.135105.

Gold microelectrodes decorated with nanotips were developed for spectroelectrochemical experiments. These new dual probes were fabricated by combining fabrication processes of scanning near-field optical microscopy with photolithography. A nanotip array was produced at the surface of a coherent optical fiber bundle by a wet chemical etching step. The resulting nanostructured surface was sputter-coated with a thin gold layer. This gold film conferred plasmonic properties to the sharp nanotips and served as well as the electrode material to enable electrochemical reactions. A photolithographic process was used to define on the bundle surface nanotips-decorated microelectrodes with tunable dimensions (radii ranging between 20 μm and 3.5 μm) individually or in an array format. The resulting microelectrodes with a regular nanotip pattern were characterized first by cyclic voltammetry. Numerical simulation was used to assess the electrochemical properties of these platforms and the influences of the recessed geometry and of the nanotips. Approach curves were recorded in negative and positive feedback modes of scanning electrochemical microscopy (SECM) on insulating and conducting substrates. Finally, spatially resolved Raman imaging allowed us to detect a mercaptobenzoic acid monolayer adsorbed on the microelectrode surface, demonstrating a surface-enhanced Raman scattering (SERS) effect induced by the gold-coated nanotips with a typical enhancement factor of ∼7 × 104. Such an approach introduces a reproducible method to fabricate promising SERS-active platforms with microelectrode behavior for SECM experiments.

tips

A. Bouchet-Spinelli, E. Descamps, J. Liu, A. Ismail, P. Pham, F. Chatelain, T. Leïchlé, L. Leroy, P. N. Marche, C. Raillon, A. Roget, Y. Roupioz, N. Sojic, A. Buhot, V. Haguet, T. Livache and P. Mailley

Biosensors 2019, 9, 121; doi:10.3390/bios9040121

This review summarizes recent advances in micro- and nanopore technologies with a focus on the functionalization of pores using a promising method named contactless electro-functionalization (CLEF). CLEF enables the localized grafting of electroactive entities onto the inner wall of a micro- or nano-sized pore in a solid-state silicon/silicon oxide membrane. A voltage or electrical current applied across the pore induces the surface functionalization by electroactive entities exclusively on the inside pore wall, which is a significant improvement over existing methods. CLEF’s mechanism is based on the polarization of a sandwich-like silicon/silicon oxide membrane, creating electronic pathways between the core silicon and the electrolyte. Correlation between numerical simulations and experiments have validated this hypothesis. CLEF-induced micro- and nanopores functionalized with antibodies or oligonucleotides were successfully used for the detection and identification of cells and are promising sensitive biosensors. This technology could soon be successfully applied to planar configurations of pores, such as restrictions in microfluidic channels.

micropore

S. Assavapanumat, M. Ketkaew, P. Garrigue, V Lapeyre, S Reculusa, C Wattanakit, A Kuhn

ChemCatChem (2019) in press

Electrochemical water splitting is a crucially important process for energy conversion and storage. In this context, we report the synthesis of hierarchical multiporous nickel nanosheets obtained by a templated two-step electrodeposition of nickel in the presence of silica beads and an assembly of nonionic surfactant in order to generate a combined macro- and mesoporous structure. Interestingly, the synergistic effect of these highly ordered meso- and macroporous structures promotes the catalytic performance for oxygen evolution reaction with one order of magnitude higher current densities and a better stability of the electrodes compared to flat nickel or electrodes having a single type of porosity. This example illustrates a promising strategy for the rational design of high-performance porous metals, not only in the frame of water electrolysis, but also for other electrocatalytic applications.

2019 14

T.D. Le, L. Zhang, A. Kuhn, N. Mano, G. Vignoles, D. Lasseux

J.Electroanal.Chem. (2019) in press

Multiscale modelling of coupled diffusion and serial reduction reactions in porous micro-electrodes is developed in this work. The governing coupled equations at the pore scale in the case of two reduction reactions, as for instance, the serial reaction pathway for oxygen reduction to hydrogen peroxide and subsequently to water, are upscaled to obtain a macroscopic model describing the process in an effective medium at the electrode scale. This new macroscopic model, obtained from the volume averaging technique, is validated through comparisons with results of 3D Direct Numerical Simulations of the pore-scale model. The excellent agreement between the two approaches proves the relevance of the macroscale model which reduces to a 1D problem in the configuration under concern, providing a drastic speedup in the computation of the solution. Numerical results obtained with the macroscopic model are successfully compared to experimental data obtained by voltammetry with porous gold electrodes of different thicknesses operating the serial pathway of oxygen reduction to water. Results highlight the ability of this new macroscopic model to predict the electrode behavior and show that the second reduction reaction of hydrogen peroxide plays an important role in the current production.

2019 15

S. Assavapanumat, B. Gupta, G. Salinas, B. Goudeau, C. Wattanakit, A. Kuhn

ChemComm 55 (2019) 10956

We report the synthesis of a hybrid bilayer, being composed of a free-standing conducting polymer film and a layer of mesoporous metal, encoded with chiral features. The resulting structure constitutes an enantioselective actuator, which can be electrochemically addressed in a wireless way. The controlled discriminatory deformation of the film allows an easy readout of chiral information.

2019 13

Thumbnail Dezest M., Bulteau A.L., Quinton D., Chavatte L., Le Béchec M., Arbault S., Salvayre A.N., Cousty S., Clément F. PLOS One, 2017, 12(3) Cold atmospheric pressure plasmas (CAPPs) are known to have...
Thumbnail C. Wattanakit, T. Yutthalekha, S. Asssavapanumat, V. Lapeyre, A. Kuhn Nature Comm. 2017, 8, 2087 see also CNRS press release Asymmetric synthesis of molecules is of crucial importance to obtain...
Thumbnail Giovanni Valenti, Sabina Scarabino, Bertrand Goudeau, Andreas Lesch, Milica Jovic, Elena Villani, Milica Sentic, Stefania Rapino, Stephane Arbault, Francesco Paolucci, and Neso Sojic J. Am. Chem....
Thumbnail V. Eßmann, S. Voci, G. Loget, N. Sojic, W. Schuhmann, A. Kuhn J. Phys. Chem. Lett. 2017,8, 4930–4934   Bipolar electrochemistry has been shown to enable and control various kinds of propulsion of...
Thumbnail Guangnan Meng, Vinothan N. Manoharan and Adeline Perro Soft Matter, 2017,13, 6293-6296 We design polystyrene–poly(N′-isopropylacrylamide-co-acrylic acid) core–shell particles that exhibit...
Thumbnail J. Gao, S. Chen, F. AlTal, S. Hu, L. Bouffier, G. Wantz.  ACS Appl. Mater. Interfaces, 2017, 9, 32405–32410.  A linear array of aluminum discs is deposited between the driving electrodes of an...
Thumbnail B. Gupta, B. Goudeau, A. Kuhn Angew.Chem. Int. Ed. 2017, 56, 14183-14186 see also Highlight in Chemistry Views and CNRS press release Electrochemical actuation of conducting polymers usually...
Thumbnail Z. Ali Fattah, L. Bouffier, A. Kuhn Applied Materials Today 2017, 9, 259–265, COVER Self-propelled micro/nanoswimmers performing directional motion are of great potential nowadays in the frame of...
Thumbnail T.D. Le, D. Lasseux, X.P. Nguyen, G. Vignoles, N. Mano, A. Kuhn Chemical Engineering Science 2017, 173, 153–167 A multi-scale model of diffusion/reaction at play in a porous electrode is developed...
Thumbnail M. Dabrowski, M. Cieplak, K. Noworyta, M. Heim, W. Adamkiewicz, A. Kuhn, P. S. Sharma, W. Kutner J. Mater. Chem. B, 2017,5, 6292-6299 Molecular imprinting in polymers leads, among others, to...
Thumbnail L. Bouffier, T. Doneux.  Current Opinion in Electrochemistry, DOI: 10.1016/j.coelec.2017.06.015. Electrochemistry and fluorescence microscopy are two complementary transduction techniques that offer synergetic...
Thumbnail G. Di Martino,V. A. Turek,  A. Lombardi, I.  Szabó, B. de Nijs,  A. Kuhn, E. Rosta, J.J. Baumberg Nano Lett. 2017, 17, 4840-4845 We study in real time the optical response of individual plasmonic...
Thumbnail Rémy Bois, Sabina Scarabino, Valérie Ravaine, Neso Sojic Langmuir, 2017, DOI: 10.1021/acs.langmuir.7b01585 We describe a method to confine electrochemiluminescence (ECL) at the oil-water interface of emulsion...
Thumbnail D. Zigah, O. Fontaine World Scientific, 2017, ISBN: 978-1-78634-353-6   Bioelectrochemical Systems (BESs) are innovative and sustainable devices. They combine biological and electrochemical...
Thumbnail C. Bodin,  E. Mourad,  D. Zigah,  S. Le Vot,  S. A Freunberger,  F. Favier, O. Fontaine Faraday Discuss., 2017,DOI: 10.1039/C7FD00174F   Nowadays, commercial supercapacitors are based on purely...
Thumbnail S. Tiewcharoen, C. Warakulwit, V. Lapeyre, P. Garrigue, L. Fourier, C. Elissalde, S. Buffière, P. Legros, M. Gayot, J. Limtrakul, A. Kuhn Angew.Chem.Int.Ed. (2017) 56, 11431-11435, COVER, HOT...
Thumbnail G. Di Martino, V. A. Turek,  C. Tserkezis, A. Lombardi, A. Kuhn, J.J. Baumberg Faraday Discuss., 2017, in press,doi 10.1039/C7FD00130D We study the optical response of individual nm-wide plasmonic...
Thumbnail A. G. Mark, E. Suraniti, J. Roche, H. Richter, A. Kuhn, N. Mano, P. Fischer Lab Chip, 2017, 17, 1761 HOT PAPER see also CNRS press release A variety of diagnostic and therapeutic medical...
Thumbnail I. Malytska, C. Mézière, M. Keilar, L. Hirsch, G. Wantz, N. Avarvari, A. Kuhn, L. Bouffier. Journal of Physical Chemistry C 2017, 121, 12921-12927.   Bipolar electrochemistry has recently emerged as a very...
Thumbnail L. Bouffier, S. Reculusa, V. Ravaine, A. Kuhn. ChemPhysChem 2017, 18, 2637-2642.   A new simple and versatile method for the preparation of surface wetting gradients is proposed. It is based on the...
Thumbnail C.A. Busatto, H. Labie, V. Lapeyre, R. Auzely-Velty, A. Perro, N. Casis, J. Luna, D.A. Estenoz, V. Ravaine Journal of Colloid and Interface Science, 493, 2017, 356–364. Polymer microgels have received...
Thumbnail L. Bouffier, N. Sojic, A. Kuhn Electrophoresis, 2017, 38, 2687-2694. A bipolar electrode is quite unconventional as it behaves simultaneously as an anode and a cathode in contrast to a classic...
Thumbnail M. Dabrowski, M. Cieplaka, P. Sindhu Sharma, P. Borowicz, K. Noworyta, W. Lisowski, F. D'Souza, A. Kuhn, W. Kutner Biosens.&Bioelectron.2017, 94, 155-161 Nanostructured artificial receptor...
Thumbnail Nenad R. Filipovic, Hana Elshaflu, Sonja Grubic, Ljiljana S. Jovanovic, Marko Rodic, Irena Novakovic, Aleksandar Malecevic, Ivana S. Djordjevic, Haidong Li, Neso Sojic, Aleksandar Marinkovic,...
Thumbnail Haidong Li, Silvia Voci, Antoine Wallabregue, Catherine Adam, Geraldine M. Labrador, Romain Duwald, Irene Hernández Delgado, Simon Pascal, Johann Bosson, Jérôme Lacour, Laurent BouffierNeso...