S. M. Beladi-Mousavi, G. Salinas, N. Antonatos, V. Mazanek, P. Garrigue, Z. Sofer, A. Kuhn
Graphene has unique characteristics that are appealing for energy-related applications such as ultra-lightweight and high surface-area/electrical-conductivity. However, generating functional graphene sheets is still a very challenging task. Here, a novel approach based on an original bipolar electrochemistry set-up, using a quasi-2D reaction layer, is suggested, which allows a precise control of dispersibility and conductivity of graphene sheets. In this system, a freestanding 2D layer of aqueous solution, containing 2D graphene oxide (GO) sheets, is placed between two platinum feeder electrodes, which are used to apply an electric field. As a result, the GO sheets experience a sufficiently high polarization to cause their transformation into reduced GO (rGO). The degree of reduction can be readily controlled by the field strength and exposure time, resulting in a wide range of rGO with different conductivity/dispersibility features. The partially reduced GO (prGO) sheets with engineered conductivity/dispersibility are used to prepare aqueous composites with a redox-polymer for organic battery applications. Additonally, at higher potentials, Pt nanoparticles are released from the feeder electrodes and attached to rGO sheets. The sheets were used for catalyzing hydrogen evolution reaction with a performance comparable to bulk Pt.
Y. Zhao, J. Descamps, S. Ababou-Girard, J.-F. Bergamini, L. Santinacci, Y. Léger, N. Sojic, G. Loget
Angew. Chem. Int. Ed., 61, 2022,DOI: 10.1002/anie.202201865
Photoinduced electrochemiluminescence (PECL) allows the electrochemically assisted conversion of low-energy photons into high-energy photons at an electrode surface. This concept is expected to have important implications, however, it is dramatically limited by the stability of the surface, impeding future developments. Here, a series of metal-insulator-semiconductor junctions, using photoactive n-type Si (n-Si) as a light absorber covered by a few-nanometer-thick protective SiOx/metal (SiOx/M, with M = Ru, Pt, and Ir) overlayers are investigated for upconversion PECL of the model co-reactant system involving the simultaneous oxidation of tris(bipyridine)ruthenium(II) and tri-n-propylamine. We show that n-Si/SiOx/Pt and n-Si/SiOx/Ir exhibit high photovoltages and record stabilities in operation (35 h for n-Si/SiOx/Ir) for the generation of intense PECL with an anti-Stokes shift of 218 nm. We also demonstrate that these surfaces can be employed for spatially localized PECL. These unprecedented performances are extremely promising for future applications of PECL.
S. Butcha, V. Lapeyre, C. Wattanakit, A. Kuhn
In modern chemistry, chiral (electro)catalysis is a powerful strategy to produce enantiomerically pure compounds (EPC). However, it still struggles with uncontrollable stereochemistry due to side reactions, eventually producing a racemic mixture. To overcome this important challenge, a well-controlled design of chiral catalyst materials is mandatory to produce enantiomers with acceptable purity. In this context, we propose the synergetic combination of two strategies, namely the elaboration of mesoporous Pt films, imprinted with chiral recognition sites, together with the spatially controlled formation of a self-assembled monolayer. Chiral imprinted metals have been previously suggested as electrode materials for enantioselective recognition, separation and synthesis. However, the outermost surface of such electrodes is lacking chiral information and thus leads to unspecific reactions. Functionalising selectively this part of the electrode with a monolayer of organosulfur ligands allows an almost total suppression of undesired side reactions and thus leads to a boost of enantiomeric excess to values of over 90% when using these surfaces in the frame of enantioselective electrosynthesis. In addition, this strategy also decreases the total reaction time by one order of magnitude. The study therefore opens up promising perspectives for the development of heterogeneous enantioselective electrocatalysis strategies.
Yiran Zhao, Laurent Bouffier, Guobao Xu, Gabriel Loget, Neso Sojic
Chem. Sci., 2022, DOI: 10.1039/D1SC06987J
Electrochemiluminescence (ECL) is the light production triggered by reactions at the electrode surface. Its intrinsic features based on a dual electrochemical/photophysical nature have made it an attractive and powerful method across diverse fields in applied and fundamental research. Herein, we review the combination of ECL with semiconductor (SC) materials presenting various typical dimensions and structures, which has opened new uses of ECL and offered exciting opportunities for (bio)sensing and imaging. In particular, we highlight this particularly rich domain at the interface between photoelectrochemistry, SC material chemistry and analytical chemistry. After an introduction to the ECL and SC fundamentals, we gather the recent advances with representative examples of new strategies to generate ECL in original configurations. Indeed, bulk SC can be used as electrode materials with unusual ECL properties or light-addressable systems. At the nanoscale, the SC nanocrystals or quantum dots (QDs) constitute excellent bright ECL nano-emitters with tuneable emission wavelengths and remarkable stability. Finally, the challenges and future prospects are discussed for the design of new detection strategies in (bio)analytical chemistry, light-addressable systems, imaging, or infrared devices.
Fatma Ben Trad, Vincent Wieczny, Jérôme Delacotte, Mathieu Morel, Manon Guille-Collignon, Stéphane Arbault, Frédéric Lemaître, Neso Sojic, Eric Labbé, Olivier Buriez
Anal. Chem., 2022, 94, 1686–1696
In this work, the characterization of release events from liposomes has been addressed quantitatively by an electrochemiluminescence (ECL) imaging strategy. First, ECL reagents ([Ru(bpy)3]2+ and tripropylamine) were encapsulated in sealed giant asymmetrical liposomes (100 μm in diameter) made of DOPG/DOPC phospholipids. After sedimentation on an indium tin oxide electrode material, the opening of liposomes was triggered by polarization of the surface. Under these conditions, amperometry, epifluorescence imaging, and ECL imaging were combined and synchronized to monitor and image the rupture of giant liposomes during the release and subsequent ECL emission of their redox content. Amperometry allowed the quantification of the content released from single liposomes. The location and status of liposomes (closed or opened) were assessed by epifluorescence imaging. ECL provided the image of the efflux of matter after liposome opening. This original ECL imaging approach favorably compares with strictly photoluminescent or electrochemical techniques and appears to be adapted for the investigation of membrane rupture/permeation events.
- Sensitive electrochemiluminescence biosensing of polynucleotide kinase using the versatility of two-dimensional Ti3C2TX MXene nanomaterials
- Benzothioxanthene Dicarboximide as a Tuneable Electrogenerated Chemiluminescence Dye
- Local pH Modulation during Electro-Enzymatic O2 Reduction: Characterization of the Influence of Ionic Strength by In Situ Fluorescence Microscopy