ORALS

SESSION: ElectrochemistryMonAM-R2	Amatore International Symposium on Electrochemistry for Sustainable Development
Mon Nov, 5 2018 / Room: Copacabana B (150/1st)
Session Chairs: Emmanuel Mousset; Session Monitor: TBA

11:20: [ElectrochemistryMonAM01] Plenary
A Combined SERS-DFT Study Towards Deep Understanding Electrocatalysis
Zhongqun Tian¹ ; Yi-fan Huang² ; Christian Amatore³ ; An Wang² ; De-yin Wu² ; Sandra Rondinini⁴ ; ¹Department of Chemistry, Xiamen Uinversity, Xiamen, China; ²Xiamen University, Xiamen, China; ³CNRS & PSL, French Academy of Sciences, Paris, France; ⁴Universita degli Studi di Milano, Milan, Italy;
Paper Id: 277 [Abstract]

Surface-enhanced Raman spectroscopy (SERS) is one of the few powerful in-situ electrochemical spectroscopies, since it is highly sensitive on the surface species and almost inert on the species in the bulk of electrolyte. However, in order to comprehensively understand electrocatalysis, EC-SERS has to be correctly understand and consistent with the electrochemistry and theory. Here, we present the EC-SERS study on the electrocatalytic reduction of benzyl chloride on Ag by combing experiments and theoretical calculations. To identify the electrode surface species, we performed DFT calculations with Raman spectroscopy on the possible reaction intermediates and products. The results show that the Raman spectrum of the negatively charged benzyl-Ag cluster shows similar spectroscopic characters as experimental spectra, which indicates benzyl anion adsorbed Ag electrode is the key intermediate of the electrocatalytic reduction of benzyl chloride on Ag. By applying the same strategy, we also studied the adsorption of benzyl chloride and the possible products. In light of the reaction pathway roughed out by the consistent EC-SERS observations and DFT simulations on the spectra, the details of the electrocatalysis regarding the binding energy and the activation energy of reactants and intermediates are revealed by electrochemical kinetics calculation combined with DFT calculation. We found that the weakly interaction between distorted benzyl chloride anion and Ag facilitates the dissociation of C-Cl bond and drives the conversion of benzyl chloride. The more detailed discussion will be given. The combined EC-SERS/DFT investigation provides a key entry for understanding the origin of electro-catalytic activity by consistent experimental observations and theoretical calculations.

References:
[1] A. Wang, Y. F. Huang, U. K. Sur, D. Y. Wu, B. Ren, S. Rondinini, C. Amatore, Z. Q. Tian, J. Am. Chem. Soc. 132(2010)9534-9536.
[2] Y. F. Huang, D. Y. Wu, A. Wang, B. Ren, S. Rondinini, Z. Q. Tian, C. Amatore, J. Am. Chem. Soc. 132(2010)17199-17210.

SESSION: ElectrochemistryMonAM-R2	Amatore International Symposium on Electrochemistry for Sustainable Development
Mon Nov, 5 2018 / Room: Copacabana B (150/1st)
Session Chairs: Emmanuel Mousset; Session Monitor: TBA

12:10: [ElectrochemistryMonAM03]
Electrochemical Activation of Carbon Dioxide for the Synthesis of Chemicals
Christian Amatore¹ ; Alessandro Galia² ; Onofrio Scialdone² ; ¹CNRS & PSL, French Academy of Sciences, Paris, France; ²University of Palermo, Palermo, Italy;
Paper Id: 63 [Abstract]

To curb the negative effect of carbon dioxide as a greenhouse gas, an interesting approach is the utilization of Carbon Capture and Conversion (CCC) methodologies. These recycling technologies are focused on the use of CO₂ waste as a feedstock for the production of industrially relevant chemicals. In the past years, increasing attention has been devoted to the electrochemical conversion of CO₂, which would combine the utilization of excess electric energy from intermittent renewable sources with the selective conversion of CO₂ into added value products. Furthermore, it would be possible, in order to reduce the costs, to use the excess of the daily produced electricity, not matching actual demand energy, that is usually lost or not properly used. Researches have shown that several products, including carbon monoxide, formic acid, methane, methanol, ethylene and oxalic acid, can be obtained by this process. Furthermore, it has been shown that carbon dioxide can be introduced in the backbone of other molecules, generating fine chemicals with high economic value, such as anti-inflammatory drugs, by cathodic reduction in aprotic solvents In this work, various routes for the electrochemical conversion of carbon dioxide will be presented and discussed from both a scientific, technical and economic point of view, such as the synthesis of formic acid in water (in conventional and pressurized cells) or the electrocarboxylation of aromatic ketones and benzyl chlorides in organic solvents, in order to illustrate the current scenario.

References:
[1] S. Sabatino, A. Galia, G. Saracco, O. Scialdone, Development of an electrochemical process for the simultaneous treatment of wastewater and the conversion of carbon dioxide to higher value products, ChemElectroChem 4 (1), 150-159, 2017.
[2] O. Scialdone, A. Galia, G.L. Nero, F. Proietto, S. Sabatino, B. Schiavo, Electrochemical reduction of carbon dioxide to formic acid at a tin cathode in divided and undivided cells: effect of carbon dioxide pressure and other operating parameter, Electrochimica Acta 199, 332-341, 2016

SESSION: ElectrochemistryMonPM1-R2	Amatore International Symposium on Electrochemistry for Sustainable Development
Mon Nov, 5 2018 / Room: Copacabana B (150/1st)
Session Chairs: Wei-Hua Huang; Session Monitor: TBA

14:50: [ElectrochemistryMonPM107]
Quantitative Analysis of Fusion Pore Dynamics During Vesicular Exocytosis in Neuroendocrine Cells
Alexander Oleinick¹ ; Irina Svir² ; Christian Amatore³ ; ¹CNRS-ENS-SU UMR 8640 PASTEUR, CNRS, Paris, France; ²Ecole Normale Superieure, Department Chemistry, PARIS, France; ³CNRS & PSL, French Academy of Sciences, Paris, France;
Paper Id: 98 [Abstract]

Vesicular exocytosis is a key biological mechanism through which cells communicate with each other or with their environment. It is involved in many systems in our body (e.g. nervous, endocrine, digestive, etc.), which makes its understanding of paramount importance from both fundamental and practical points of view. Amperometric measurements of vesicular exocytosis with ultramicroelectrode in artificial synapse configuration [1] provide two important advantages: unsurpassed temporal resolution on emitted fluxes of neurotransmitter during single exocytotic events and possibility to obtain massive data. These two advantages allow statistical analysis of exocytotic events and observe trends in different cell types and/or under various physico-chemical conditions (osmotic shocks, effect of drugs etc.). However, generally statistical analysis is restricted to the examination of some shape features of the amperometric spikes (half-peak time width, charge released etc.) representing individual exocytotic events, even though all relevant physico-chemical parameters are intricately convoluted in the monitored current. Extraction of these thought parameters is extremely difficult, due to the fact that each exocytotic event is unique in terms of vesicle size, its internal composition, neurotransmitter load etc. We developed a theoretical framework providing means to extract statistically sound fusion pore sizes during exocytotic event from individual amperometric spikes [2-3], that is the information hardly accessible or not accessible by other approaches. This permits us to analyze and quantify vesicle pore sizes from amperometric data obtained at bovine chromaffin cells [4]. Recently we dramatically simplified the fusion pore size extraction procedure (without sacrificing its accuracy) so that it can be easily implemented by the experimentalists, e.g. in spreadsheet or general purpose mathematical software. This advance allow us to address a larger data set of spikes obtained at chromaffin cells and reveal statistical changes in fusion pores topology under modified conditions (osmotic stress, modification of cell membrane with exogeneous lipids) with respect to control conditions. Of high interest was the finding that in all considered cases the fusion pore radius was never larger than 30 nm, that is much smaller to the average radius of the chromaffin cell vesicle (156 nm). Taking into account significant size of the data set (more than 1000 spikes) this questions the 'inevitable full fusion' paradigm and statistically support a mode of exocytosis where the pore size is significantly smaller the vesicle size [4].

References:
[1] C. Amatore, S. Arbault, M. Guille, F. Lemaitre. Chem. Rev. 108 (2008) 2585-2621.
[2] C. Amatore, A. Oleinick, I. Svir. ChemPhysChem 11 (2010) 149-158; 159-174.
[3] A. Oleinick, F. Lemaitre, M. Guille Collignon, I. Svir, C. Amatore. Faraday Discuss. 164 (2013) 33-55.
[4] A. Oleinick, I. Svir, C. Amatore. Proc. Roy. Soc. A 473 (2017) 20160684.

SESSION: ElectrochemistryTuePM2-R2	Amatore International Symposium on Electrochemistry for Sustainable Development
Tue Nov, 6 2018 / Room: Copacabana B (150/1st)
Session Chairs: Lauro Tatsuo Kubota; Session Monitor: TBA

16:20: [ElectrochemistryTuePM210]
Simultaneous Electrochemical Detection of Primary Reactive Oxygen and Nitrogen Species Released by Cell Populations in Integrated Microdevices
Yun Li¹ ; Catherine Sella¹ ; Frederic Lemaitre¹ ; Manon Guille Collignon¹ ; Christian Amatore² ; Laurent Thouin¹ ; ¹Ecole normale superieure - CNRS, Paris, France; ²CNRS & PSL, French Academy of Sciences, Paris, France;
Paper Id: 383 [Abstract]

Innovative microdevices were designed to monitor electrochemically primary reactive oxygen (ROS) and reactive nitrogen species (RNS) released by populations of aerobic cells. Taking advantage of the space confinement and microelectrodes performances, only few experiments were sufficient to provide significant statistical data relative to the average behavior of cells during oxidative stress bursts.<br />Platinum-black coated platinum (Pt/Pt-black) electrodes were microfabricated and optimized to achieve optimal performance during the electrochemical detection of four primary species H₂O₂, NO, ONOO^- and NO₂^-.^1,2 The results demonstrated that relative ROS/RNS contents in synthetic mixtures can be easily assessed at selected detection potentials. Under given experimental conditions, the Pt/Pt-black electrodes allow detection limits down to 10 nM with high sensitivities and long-term stability of the electrodes responses.<br />The electrochemical detection of ROS/RNS released by cell populations was then implemented in a multi-chambers microsystem³ and in a microfluidics device.⁴ As an important cell type, RAW 264.7 macrophages secretion triggered by a calcium ionophore was chosen for assessing the performance, sensitivity and specificity of the detection in both cases. In comparison to some previous evaluations obtained from single-cell measurements, reproducible and relevant determinations could be achieved. However, separating emitting cells from the detection area in the microfluidic device seems to be a better approach to avoid any perturbations of cell behaviors by electrode operations. Furthermore, any biological effects during oxidative stress of living cells can be easily investigated. As a proof of concept, we reported the analysis of the influence of a NO synthase inhibitor during the perfusion culture.

References:
(1) Li, Y.; Sella, C.; Lemaitre, F.; Guille-Collignon, M.; Thouin, L.; Amatore, C. Electroanalysis 2013, 25, 895-902. DOI 10.1002/elan.201200456.\n(2) Li, Y.; Sella, C.; Lemaitre, F.; Guille-Collignon, M.; Thouin, L.; Amatore, C. Electrochim. Acta 2014, 144, 111-118. DOI 10.1016/j.electacta.2014.08.046.\n(3) Li, Y.; Meunier, A.; Fulcrand, R.; Sella, C.; Amatore, C.; Thouin, L.; Lemaitre, F.; Guille-Collignon, M. Electroanalysis 2016, 28, 1865-1872. DOI 10.1002/elan.201501157.\n(4) Li, Y.; Sella, C.; Lemaitre, F.; Collignon, M. G.; Amatore, C.; Thouin, L. Anal. Chem. 2018. DOI 10.1021/acs.analchem.8b02039.

SESSION: ElectrochemistryTuePM2-R2	Amatore International Symposium on Electrochemistry for Sustainable Development
Tue Nov, 6 2018 / Room: Copacabana B (150/1st)
Session Chairs: Lauro Tatsuo Kubota; Session Monitor: TBA

17:10: [ElectrochemistryTuePM212] Invited
Innovative Electrochemical Processes and Reactors for the Treatment of Wastewater
Onofrio Scialdone¹ ; Christian Amatore² ; ¹University of Palermo, Palermo, Italy; ²CNRS & PSL, French Academy of Sciences, Paris, France;
Paper Id: 62 [Abstract]

The electrochemical treatment of wastewater contaminated by organic and inorganic pollutants resistant to conventional processes is considered a very promising and appealing approach. The most interesting processes are the electrochemical direct oxidation, the indirect oxidation by electro-generated active chlorine, and the electro-Fenton. However, various problems limit the potential application of such methodologies [1], such as the cost of electric energy necessary to drive the process; the costs due to the addition of electrolyte for wastewater with low conductivity; the low current efficiencies due to the low mass transfer for low concentrations of pollutants. In this work, various innovative approaches to solve or minimize such problems will be presented and discussed, such as the utilization of microfluidic cells (for both direct anodic oxidation and electro-Fenton) [2,3], pressurized reactors (for electro-Fenton) [4], microbial fuel cells [5] and reverse electrodialysis [6]. It will be shown that the utilization of such processes can drastically improve the performances of various electrochemical processes for the treatment of wastewater. In particular, the activation of various molecules able to oxidize organic pollutants will be discussed.

References:
[1] C.A. Martinez-Huitle, M.A. Rodrigo, I. Sires, O. Scialdone, Single and coupled electrochemical processes and reactors for the abatement of organic water pollutants: a critical review. Chemical reviews 115, 13362-13407, 2015.
[2] O. Scialdone, A. Galia, S. Sabatino, Electro-generation of H2O2 and abatement of organic pollutant in water by an electro-Fenton process in a microfluidic reactor, Electrochemistry communications 26, 45-47; O Scialdone, A. Galia, S. Sabatino, Abatement of Acid Orange 7 in macro and micro reactors. Effect of the electrocatalytic route. Applied Catalysis B: Environmental 148, 473-48, 2015.
[3] O. Scialdone, C. Guarisco, A. Galia, G. Filardo, G. Silvestri, C, Amatore, Anodic abatement of organic pollutants in water in micro reactors, Journal of Electroanalytical Chemistry 638 (2), 293-296.
[4] O. Scialdone, A. Galia, C Gattuso, S Sabatino, B Schiavo, Effect of air pressure on the electro-generation of H 2 O 2 and the abatement of organic pollutants in water by electro-Fenton process, Electrochimica Acta 182, 775-780
[5] G Riccobono, G Pastorella, F Vicari, A D'Angelo, A Galia, P Quatrini, Abatement of AO7 in a divided microbial fuel cells by sequential cathodic and anodic treatment powered by different microorganisms, Journal of Electroanalytical Chemistry
[6] O. Scialdone, A. D'Angelo, E. De Lume, A. Galia, Cathodic reduction of hexavalent chromium coupled with electricity generation achieved by reverse-electrodialysis processes using salinity gradients, Electrochimica Acta 137, 258-265, 2014; A. D'Angelo, M. Tedesco, A. Cipollina, A. Galia, G. Micale, O. Scialdone, Reverse electrodialysis performed at pilot plant scale: Evaluation of redox processes and simultaneous generation of electric energy and treatment of wastewater, Water research 125, 123-131, 2017.