IR and electrochemical synthesis and characterization of thin films of PEDOT grown on platinum single crystal electrodes in [EMMIM]Tf2N ionic liquid

Thin films of PEDOT synthesized on platinum single electrodes in contact with the ionic liquid 1-ethyl-2,3-dimethylimidazolium triflimide ([EMMIM]Tf2N) were studied by cyclic voltammetry, chronoamperometry, infrared spectroscopy and atomic force microscopy. It was found that the polymer grows faster on Pt(111) than on Pt(110) or Pt(100) and that the redox reactions associated with the PEDOT p-doping process are much more reversible in [EMMIM]Tf2N than in acetonitrile. Finally, the ion exchange and charge carriers’ formation during the p-doping reaction of PEDOT were studied using in situ FTIR spectroscopy.APS acknowledges the scholarship “Estudiantes sobresalientes de posgrado” at the “Universidad Nacional de Colombia (UNAL)” and COLCIENCIAS National Doctoral Scholarship (567). MFS acknowledges support of UNAL (Research Project 19030). JMF thanks MINECO (Spain) support through project CTQ2013-44083-P and Generalitat Valenciana (Feder) through project PROMETEOII/2014/013

Hydrogen redox reactions in 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide on platinum single crystal electrodes

Hydrogen oxidation and the subsequent proton reduction are studied on platinum single crystal electrodes in purified 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid. The hydrogen redox reaction shows some dependence of the surface orientation. The highest reversibility is observed with Pt(111) whereas the reaction in electrodes with {100} sites is less reversible and with a slow kinetics. Adsorption states are observed in the presence of hydrogen along with the main oxidation reaction. Also, it is possible to detect protons after oxidation of water and H2O2.APS is grateful to the National University of Colombia (ESP-2011-02) for the scholarship “Estudiantes sobresalientes de posgrado”, and to COLCIENCIAS (567-2012) for the national doctoral scholarship. MFS acknowledges support from the National University of Colombia (Research Project 19030). JMF acknowledges support from Generalitat Valenciana (Feder) (PROMETEO/2009/045) through project PROMETEO/2009/045

Interaction of water with methanesulfonic acid on Pt single crystal electrodes

The electrochemical behavior of methanesulfonic acid on platinum single crystal electrode surfaces is investigated by cyclic voltammetry and infrared spectroscopy measurements. The results are compared with the voltammetric profiles of perchloric and trifluoromethanesulfonic acids. The differences are interpreted in terms of the effect of the anion on the structure of water. No adsorbed species are detected by infrared spectroscopy.APS acknowledges the scholarship “Estudiantes sobresalientes de posgrado” at the UNC and COLCIENCIAS National Doctoral Scholarship (567). MFS acknowledges the support of UNC (Research Project 19030). JMFwould like to thankGeneralitat Valenciana (Feder) through project PROMETEOII/2014/013

Role of the interfacial water structure on electrocatalysis: Oxygen reduction on Pt(1 1 1) in methanesulfonic acid

Most of electrocatalytic reactions occur in an aqueous environment. Understanding the influence of water structure on reaction dynamics is fundamental in electrocatalysis. In this work, the role of liquid water structure on the oxygen reduction at Pt(1 1 1) electrode is analyzed in methanesulfonic (MTSA) and perchloric acids. This is because these different anions can exert a different influence on liquid water structure. Results reveal a lower ORR electrode activity in MTSA than in HClO4 solutions and they are discussed in light of anion's influence on water structural ordering. From them, the existence of an outer-sphere, rate determining, step in the ORR mechanism is suggested.This work has been carried out under MINECO project CTQ2013-44083-P (Spain). APSR acknowledges the scholarship “Estudiantes sobresalientes de posgrado” at the UNAL and COLCIENCIAS National Doctoral Scholarship (567). MFS acknowledges the support of UNAL (Research Project 19030)

Electrochemical reduction of CO2 in water-acetonitrile mixtures on nanostructured Cu electrode

This communication studies the CO2 reduction reaction in H2O/CH3CN mixtures on nanostructured copper. It was found that the nanostructured copper electrode presents a well-defined voltammogram in acetonitrile, where it can be seen three signals related to adsorbed or surface attached (thin films) species. Also, it was found that the current density of CO2 reduction in mixtures H2O/CH3CN on nanostructured copper electrodes with a mole fraction around 0.25 is higher than those observed with mole fractions lower than 0.15 or higher than 0.35. Finally, nanostructured Cu electrodes show higher catalytic activity towards the CO2 reduction than copper electrode.APSR acknowledges the scholarship “Estudiantes sobresalientes de posgrado” at the “Universidad Nacional de Colombia (UNAL)” and COLCIENCIAS National Doctoral Scholarship (567). MFS acknowledges the support of UNAL (Research Project 19030)

On the non-ideal behaviour of polarised liquid-liquid interfaces

peer-reviewedInterpretation of electrochemical data generated at the interface between two immiscible electrolyte solutions (ITIES), and realisation of the ITIES for technological applications, requires comprehensive knowledge of the origin of the observed currents (i.e., capacitive, ion or electron transfer currents) and the factors influencing the electrical double layer. Upon formation, the ITIES is away from equilibrium and therefore is a close approximation, but not a perfect realisation, of an ideally polarisable interface. Nevertheless, the formalism of equilibrium thermodynamics, e.g., the Nernst equation, are universally applied to interpret electrochemical processes at the ITIES. In this study, electrochemical impedance spectroscopy (EIS), cyclic and AC voltammetry were applied to probe electrochemical processes at an ITIES formed between aqueous and α,α,α-trifluorotoluene electrolyte solutions. A significant contribution from faradaic currents is observed across the whole polarisable potential window and the electrolyte solution is not an ideal resistor (especially at high electric field frequencies). The electrical double-layer at the interface is influenced by the nature of the ions adsorbed. Small inorganic ions, such as sulfate anions and aluminium cations, are shown to absorb at the interface, with methanesulfonic acid absorbing strongly. The nature of ions adsorbed at the interface shifts the potential of zero charge (PZC) at the ITIES, which we propose in turn influences the kinetics of ion transferACCEPTEDpeer-reviewe

Search for top squark pair production in pp collisions at root s=13 TeV using single lepton events

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Search for supersymmetry in events with photons and missing transverse energy in pp collisions at 13 TeV

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Search for narrow resonances in dilepton mass spectra in proton-proton collisions at root s=13 TeV and combination with 8 TeV data

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Search for heavy gauge W ' bosons in events with an energetic lepton and large missing transverse momentum at root s=13TeV

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