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International audience; We propose in this work a stepwise approach to construct photoelectrodes. This takes advantage of the self-assembly interactions between thiol with a gold surface and terpyridine ligands with first-row transition metals. Here, a [Ru(bpy)3]2+ photosensitive center bearing a free terpyridine group has been used to construct two linear dyads on gold (Au/[ZnII–RuII]4+ and Au/[CoIII–RuII]5+). The stepwise construction was characterized by electrochemistry, quartz crystal microbalance, and atomic force microscopy imaging. The results show that the dyads behave as rigid layers and are inhomogeneously distributed on the surface. The surface coverages are estimated to be in the order of 10–11 mol cm–2. The kinetics of the heterogeneous electron transfer is determined on modified gold ball microelectrodes using Laviron’s formula. The oxidation rates of the terminal Ru(II) subunits are estimated to be 700 and 2300 s–1 for Au/[ZnII–RuII]4+ and Au/[CoIII–RuII]5+, respectively. In the latter case, the rate is limited by the kinetics of electron transfer between an intermediate Co(II) center and the gold surface. For Au/[ZnII–RuII]4+, the Zn-bis-terpyridine center is not involved in the electron-transfer process and the oxidation of the Ru(II) subunit occurs through a superexchange process. In the presence of a tertiary amine in solution, the electrodes at a bias of 0.12 V behave as photoanodes when subjected to visible light irradiation. The magnitude of the photocurrent is around 10 μA cm–2 for Au/[CoIII–RuII]5+ and 5 μA cm–2 for Au/[ZnII–RuII]4+, proving the importance of an electron relay on the photon-to-current conversion. The results suggest an efficient conversion for Au/[CoIII–RuII]5+, since each bound dyad, once excited, injects an electron around 10 times per second.

An efficient nanocomposite anode material for the oxygen evolution reaction (OER) based on nickel oxide nanoparticles entrapped in a polypyrrole matrix has been readily synthesized by an all-electrochemical procedure. Examples of anodes for the OER utilizing metallic nanoparticles dispersed in an organic polymer film are still scarce but very promising for water splitting applications. Herein, nickel metal (Ni0) nanoparticles were first electrodeposited into a cationic poly(pyrrole-ammonium) film (poly1) electropolymerized onto carbon or ITO electrodes by reduction of an anionic nickel oxalate complex in aqueous borate buffer at pH 6. The Ni0 nanoparticles were then electro-oxidized into nickel oxide (NiOx) in aqueous borate buffer at pH 9.2. The physical, chemical and electrocatalytic properties of the nanostructured poly1–NiOx material were evaluated by inductively coupled plasma mass spectroscopy (ICP-MS), atomic force microscopy (AFM) and transmission electron microscopy (TEM) coupled to various electrochemical techniques, and the results were compared with those of NiOx directly deposited on a naked electrode (without polymer) by the same electrochemical procedure. Such characterization clearly evidences the beneficial role of the poly1 matrix to generate smaller and non-agglomerated NiOx particles. Owing to the small size of NiOx nanoparticles (ca. 21 nm) and the great nanostructuration of the poly1–NiOx composite film deposited on the carbon (C) electrode surface, this material displays a very high electrocatalytic OER performance in a nearly neutral solution (pH 9.2) and even in alkaline solution (pH 14) with strong mass activities and turnover frequencies (TOFs) (1.12 A mg−1 and 0.17 s−1, respectively, at an overpotential of 0.61 V at pH 9.2, and of 1.28 A mg−1 and 0.19 s−1, respectively, at an overpotential of 0.35 V at pH 14). This performance places the C/poly1–NiOx electrode among the most active anodes based on nickel oxide reported in the literature and undoped with iron ions for the OER. In addition, when the poly1–NiOx film is deposited on a porous ITO electrode, its physisorption on the electrode surface is significantly enhanced, as shown by long-term electrocatalysis at 1.2 V vs. Ag/AgCl. Indeed, its catalytic current remains constant after several days of electrocatalysis, demonstrating the great stability of the poly1–NiOx nanocomposite; the polymer matrix maintains the integrity of the NiOx nanoparticles and precludes their corrosion. This material is thus very promising for the implementation of efficient and highly stable anodes for water oxidation.

Nanocomposite anode materials for water oxidation have been readily synthesized by electrodeposition of iridium oxide nanoparticles into poly(pyrrole-alkylammonium) films, previously deposited onto carbon electrodes by oxidative electropolymerization of a pyrrole-alkylammonium monomer. The nanocomposite films were characterized by electrochemistry, transmission electron microscopy, and atomic force microscopy. They showed an efficient electrocatalytic activity toward the oxygen evolution reaction. Data from Tafel plots have demonstrated that the catalytic activity of the iridium oxide nanoparticles is maintained following their inclusion in the polymer matrix. Bulk electrolysis of water at carbon foam modified electrodes have shown that the iridium oxide-polymer composite presents a higher catalytic activity and a better operational stability than regular oxide films.

Synthesis of conducting PEDOT is achieved through an original soft alternative way: radiolysis of aerated aqueous solutions of EDOT in the absence of any external chemical initiators. The oxidation of EDOT monomers is shown to be initiated by HO . hydroxyl radicals produced by water radiolysis. A recurrent step-by-step oxidation process leads to self-assembled hydrophilic PEDOT polymers which are evidenced in solution by cryo-TEM and after centrifugation and deposition by AFM and ATR-FTIR techniques. Optical and conducting properties of radiosynthesized PEDOT-containing layers, which are respectively evaluated by UV-visible absorption spectroscopy and by cyclic voltammetry, are found to be close to those of usually electrosynthesized PEDOT layers.

a b s t r a c t Chemical sensor based on molecularly imprinted conducting polymers (MICP) is described. Polythio- phenes - acetic acid thiophene MICP films with different thicknesses have been electrosynthesized over the sensing area of an original electrochemical surface acoustic wave sensor (ESAW). To investigate the sensing properties of the developed sensor, electrochemical and gravimetric combined transductions have been applied to atrazine (ATZ) detection. Films of poly(3,4-ethylenedioxythiophene) noted PEDOT as well as non imprinted conducting polymers (NICP), were also prepared, in order to lead a compar- ative study. The structure of all films was investigated by IR spectroscopy (ATR-FTIR) and atomic force microscopy (AFM). Films growth and their doping/undoping processes were investigated by simultane- ous gravimetric/electrochemical transduction. Real time measurements highlighted difference between the two polymers electrosynthesis kinetics. MICP and NICP films grow linearly with time, whereas PEDOT film thickness presents a limit value of 1 m in the implied conditions. Considering ESAW sensor response towards charge "transfer", a linear relationship between sensor phase variations and charges density have been found for PEDOT film, with a sensitivity of about 470 ◦ C−1 cm2. The same sensitivity can also be

Starting from thiophene-based functional monomers (FM), namely, TMA, TAA, TMeOH, EDOT, and Th, bonded to atrazine (ATZ) target molecules into FM/ATZ prepolymerization dimers in acetonitrile solutions, differently functionalized molecularly imprinted conducting polymers (FM-MICP) are electrosynthesized and then washed and used as sensitive layers for ATZ recognition. Sensitivity of these layers toward ATZ, which is quantified by cyclic voltammetric measurements, decreases in the following order of functional monomers: TMA, TAA, TMeOH, EDOT, and Th. Absolute values of the FM-ATZ dimerization free energies are calculated with the help of DFT/PCM calculations and of an empirical correction of the entropy effects, using a modified Wertz formula. A strong correlation is found between FM-MICP sensitivity and the amount of FM/ATZ prepolymerization complexes.

Herein we report the development of a chemical sensor based on Molecularly Imprinted Conducting Polymers (MICP) electrosynthesized over the sensing area of a lithium tantalate Surface Acoustic Wave (SAW) sensor. In our conditions, MICP films operate as electroactive receptor layers dedicated to the detection of atrazine target molecules. Film formation in the presence of atrazine, atrazine extraction and its further recognition by MICP, are followed by combined surface acoustic wave and electrochemical transductions. Real time simultaneous measurements allow the estimation of the times necessary for the different processes, which are found to be largely inferior to those mentioned in the literature. The developed system allows thus a better understanding of the MICP recognition process.

Due to their chemical properties, stabilities and ease of process, conducting polymers (CPs) and semiconducting polymers (SCPs), found a permanent place in chemical and biological sensors. They can either participate in sensing mechanisms or immobilizing the component responsible for sensing the analyte. This article covers main recent applications of CPs and SCPs in chemical and biological sensing. The first part is focused on their chemical synthesis and deposition techniques. The second part is devoted to some interesting possibilities offered by conducting polymers in the field of chemical sensors. The last part gives an overview of CPs-based biosensors, supported by recent works.

The design of more efficient catalytic electrodes remains an important objective for the development of water splitting electrolyzers. In this context a structured composite cathode material has been synthesized by electrodeposition of molybdenum sulfide (MoSx) into a poly(pyrrole-alkylammonium) matrix, previously coated onto carbon electrodes by oxidative electropolymerization of a pyrrole-alkylammonium monomer. The composite material showed an efficient electrocatalytic activity toward proton reduction and the hydrogen evolution reaction (HER). Data from Tafel plots have demonstrated that the electron transfer rate in the composite films is fast, in agreement with the high catalytic activity of this cathode material. Bulk electrolysis of acidic water at carbon foam electrodes modified with the composite have shown that the cathodes display a high catalytic activity and a reasonable operational stability, largely exceeding that of regular amorphous MoSx electrodeposited on naked carbon foam. The enhanced catalytic performances of the composite electrode material were attributed to the structuration of the composite, which led to a homogeneous distribution of the catalyst on the carbon foam network, as shown by SEM characterizations.

The development of photoelectrochemical devices for solar light-driven water splitting and H2 production requires new strategies for the fabrication of materials that combine the necessary photoredox and catalytic properties, to allow the hydrogen evolution reaction (HER) to take place at a low overvoltage under visible light irradiation. We report the first example of a structured composite, synthesized by electrodeposition of MoSx cocatalyst into a photosensitive Ru complex film deposited onto carbon electrodes by electropolymerization of a pyrrole-functionalized Ru(II)(2,2'-bipyridine)3(2+). Composite films show efficient photocatalytic activity for HER. Our study highlights the great simplicity of this versatile electrochemical procedure to synthesize photocathodes.