Search results for "electrochemical"

σ-Hammett parameter: a strategy to enhance both photo- and electro-luminescence features of heteroleptic copper(i) complexes

2017

This work studies the effect of the σ-Hammett parameter (σp) – i.e., the σ-donation effect caused by substitution at the para position of a bipyridine ligand (4,4′-R2bipy, where R is MeO, Me, H, NO2) – on both the photo- and electro-luminescence features of a series of heteroleptic copper(I) complexes – i.e., [Cu(N^N)(P^P)]+ where N^N and P^P ligands are R2bipy and Xantphos, respectively. By virtue of a comprehensive photophysical, theoretical, and thin-film lighting device – i.e., light-emitting electrochemical cells (LECs) – investigation, we note a clear relationship between the σp and the photo- and electro-luminescence parameters, such as photoluminescence quantum yields, excited-state…

Identification of 5,6,7,8-tetrahydropterin and 5,6,7,8-tetrahydrobiopterin in Drosophila melanogaster.

1988

Summary Using reversed-phase high-performance liquid chromatography with electrochemical detection we have demonstrated the occurrence of 5,6,7,8-tetrahydropterin and 5,6,7,8-tetrahydrobiopterin in Drosophila melanogaster . The former is the first time that has been detected in vivo . The identification has been based on the retention times, hydrodinamic voltagrams and the differential concentration in three strains of Drosophila melanogaster . Compared to the wild type, the Punch 2 mutant has diminished levels of both pteridines, whereas Henna-recessive 3 lacks completely tetrahydropterin and has increased levels of tetrahydrobiopterin, as expected according to their biochemical lesions.

Electrochemical conversion of carbon dioxide: effect of the cell and of the operating parameters on the performances of the process.

2017

Recycling technologies of CO2 allow to introduce renewable energy in the chemical and energy chain, storing a renewable energy in the chemical form. In this context, electrochemical conversion of CO2 is considered one of the more interesting approaches, using excess electric energy from intermittent renewable sources. (1) Furthermore, products can be selectively controlled by changing the operating conditions of electrolysis. In particular, in the last years, an increasing attention has been devoted to the electrochemical conversion of CO2 to formic acid or formate in water. (2,3,4) The main hurdle of the reduction of CO2 from water solution is the low CO2 solubility in water. In this work,…

Physico-chemical characterization of passive films on 316L stainless steel grown in high temperature water

2014

Grand canonical rate theory for electrochemical and electrocatalytic systems I: General formulation and proton-coupled electron transfer reactions

2020

A generally valid rate theory at fixed potentials is developed to treat electrochemical and electrocatalytic potential-dependent electron, proton, and proton-coupled electron reactions. Both classical and quantum reactions in adiabatic and non-adiabatic limits are treated. The applicability and new information obtained from the theory is demonstrated for the gold catalyzed acidic Volmer reaction.

Electrochemical synthesis and physico-chemical characterization of CdSe nanotubes

2012

Green Light-Emitting Solid-State Electrochemical Cell Obtained from a Homoleptic Iridium(III) Complex Containing Ionically Charged Ligands

2006

An efficient bluish-green light-emitting Ir(III) complex was prepared by introducing charged side groups onto phenylpyridine ligands. Green light emission with a first maximum at 487 nm (CIE coordinates x = 0.337 and y = 0.501) was observed from a single layer light-emitting electrochemical cell using this new complex; this is the lowest wavelength observed so far for devices based on ionic transition metal complexes.

Anodic abatement of organic pollutants in water in micro reactors

2010

The electrochemical oxidation of oxalic acid (OA) was performed in a micro flow cell equipped with a boron doped diamond (BDD) anode. This preliminary study demonstrates that a flow cell with a micrometric distance between the cathode and the anode can be used to perform the electrochemical treatment of waters contaminated by organic pollutants in the absence of added supporting electrolytes with high abatements. The effect of the distance between the cathode and the anode, the flow rate and the current density on the abatement of oxalic acid and on the current efficiency was in particular studied.

Electrochemical Characterization of Egyptian Blue Pigment in Wall Paintings Using the Voltammetry of Microparticles Methodology

2013

The solid state voltammetric response of Egypt blue, Han blue and ploss blue pigments upon attachment to graphite electrodes in contact with aqueous phosphate buffer at pH 7.0 is studied by voltammetry of microparticles and scanning electrochemical microscopy. Such voltammetric responses, combined with those for synthetic specimens consisting of binary mixtures of the pigment and SiO2 or CaCO3 as well as ternary ones of CaCO3 and SiO2 mixtures allow for the identification of the pigment and the support in samples from wall paintings using different electrochemical parameters, in particular upon performing the Tafel and modified Tafel analysis of voltammetric peaks. Identification of Egypt b…

The Influence of the Proton Gradient on the Activation of Ferredoxin-NADP+-oxidoreductase by Light

1988

Ferredoxin-NADP+-oxidoreductase (FNR, EC 1.18.1.2) has been shown to be activated by light within a few seconds during dark-light transitions and inactivated in the dark. In previous papers this could be pointed out by the correlation of cytochrome f induction kinetics to the rate of NADP-photoreduction and the variable fluorescence. The present study deals with the role of the proton gradient during the activation process. The transition from an inactive to an active form is followed continuously in an in situ system. The steady-state rate of NADP-photoreduction is affected only by ionophores which inhibit a formation of the proton gradient, but not by inhibitors of the electric field. It …