Search results for "Electrocatalysi"
showing 10 items of 39 documents
Monofunctional pyrenes at carbon nanotube electrodes for direct electron transfer H2O2 reduction with HRP and HRP-bacterial nanocellulose
2021
Abstract The non-covalent modification of carbon nanotube electrodes with pyrene derivatives is a versatile approach to enhance the electrical wiring of enzymes for biosensors and biofuel cells. We report here a comparative study of five pyrene derivatives adsorbed at multi-walled carbon nanotube electrodes to shed light on their ability to promote direct electron transfer with horseradish peroxidase (HRP) for H2O2 reduction. In all cases, pyrene-modified electrodes enhanced catalytic reduction compared to the unmodified electrodes. The pyrene N-hydroxysuccinimide (NHS) ester derivative provided access to the highest catalytic current of 1.4 mA cm−2 at 6 mmol L−1 H2O2, high onset potential …
Abatement of Acid Orange 7 in macro and micro reactors. Effect of the electrocatalytic route
2014
Abstract The electrochemical treatment of aqueous solutions contaminated by Acid Orange 7 (AO7) was widely studied with the main objective to evaluate as the electrocatalytic route affects the performances of the degradation process in macro and microfluidic cells. Direct anodic oxidation (EO), electro-Fenton (EF), electro-generation of active chlorine (IOAC) and coupled processes were investigated in macro and microfluidic reactors in order to select more effective conditions for the treatment of such compound. The effect of numerous operative parameters (such as nature of the electrode materials, coupling of processes, flow rate, current density and inter-electrode distance) on the perfor…
Adiabatic versus non-adiabatic electron transfer at 2D electrode materials
2021
2D electrode materials are often deployed on conductive supports for electrochemistry and there is a great need to understand fundamental electrochemical processes in this electrode configuration. Here, an integrated experimental-theoretical approach is used to resolve the key electronic interactions in outer-sphere electron transfer (OS-ET), a cornerstone elementary electrochemical reaction, at graphene as-grown on a copper electrode. Using scanning electrochemical cell microscopy, and co-located structural microscopy, the classical hexaamineruthenium (III/II) couple shows the ET kinetics trend: monolayer > bilayer > multilayer graphene. This trend is rationalized quantitatively through th…
eta1-Allypalladium complexes with tridentate PNP’ ligand for the assembly of modified Screen Printed Electrodes: an electrochemical study.
2015
Specific Pd-based organometallic complex, in particular the [Pd(η1-CH2–CH=CH2)(P–N–P’)]BF4 was used for the assembly of chemically modified Screen Printed Electrodes (SPEs) and their electrochemical reactivity was also investigated. For this purpose potassium ferricyanide, hexaammineruthenium(III) chloride, sodium hexachloroiridate-(III) hydrate, ascorbic acid (AA), uric acid (UA), acetaminophen (Ac), guanine (G) and adenine (A) were used to study the electron-transfer processes, which occurred at modified SPEs, fabricated by using the [Pd(η1-CH2–CH=CH2)(P–N–P’)]BF4, applying the drop casting procedure. Interesting results were obtained in the case of the guanine (G) quantitative detection,…
Electro- and Photo-driven Reduction of CO 2 by a trans -(Cl)-[Os(diimine)(CO) 2 Cl 2 ] Precursor Catalyst: Influence of the Diimine Substituent and A…
2016
A series of [OsII(NN)(CO)2Cl2] complexes where NN is a 2,2′-bipyridine ligand substituted in the 4,4′ positions by H (C1), CH3 (C2), C(CH3)3 (C3), or C(O)OCH(CH3)2 (C4) has been studied as catalysts for the reduction of CO2. Electrocatalysis shows that the selectivity of the reaction can be switched toward the production of CO or HCOO− with an electron-donating (C2, C3) or -withdrawing (C4) substituent, respectively. The electrocatalytic process is a result of the formation of an Os0-bonded polymer, which was characterized by electrochemistry, UV/Visible and EPR spectroscopies. Photolysis of the complexes under CO2 in DMF+TEOA produces CO as a major product with a remarkably stable turnover…
Computational Screening of Doped Graphene Electrodes for Alkaline CO2 Reduction
2020
The electrocatalytic CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) is considered as one of the most promising approaches to synthesizing carbonaceous fuels and chemicals without utilizing fossil resources. However, current technologies are still in the early phase focusing primarily on identifying optimal electrode materials and reaction conditions. Doped graphene-based materials are among the best CO<sub>2</sub>RR electrocatalysts and in the present work we have performed a computational screening study to identify suitable graphene catalysts for CO<sub>2</sub>RR to CO under alkaline conditions. Several types of modified-graphene frame…
Fundamentals of photoelectrocatalysis
2022
Photoelectrocatalysis combines heterogeneous photocatalysis and electrocatalysis principles for numerous processes including the degradation of harmful compounds, the generation of H2 and O2 from water splitting, the reduction of CO2 or the photoelectrocatalytic synthesis of valuable organic molecules otherwise difficult to be synthetized with classical approaches. The recent progress of photoelectrocatalysis is heavily related to the development of materials, especially in 2D and nano materials. Highly ordered nanomaterials such as graphene, nanotubes, nanowires, etc. are gaining more attention due to their high surface area and excellent conductivity. Other challenges are the development …
A critical review on latest innovations and future challenges of electrochemical technology for the abatement of organics in water
2023
Updated water directives and ambitious targets like the United Nations’ Sustainable Development Goals (SDGs) have emerged in the last decade to tackle water scarcity and contamination. Although numerous strategies have been developed to remove water pollutants, it is still necessary to enhance their effectiveness against toxic and biorefractory organic molecules. Comprehensive reviews have highlighted the appealing features of the electrochemical technologies, but much progress has been made in recent years. In this timely review, a critical discussion on latest innovations and perspectives of the most promising electrochemical tools for wastewater treatment is presented. The work describes…
Visible-light photoelectrodegradation of diuron on WO3 nanostructures
2018
[EN] The degradation of pesticide diuron has been explored by photoelectrocatalysis (PEC) under visible light illumination using two different WO3 nanostructures, obtained by anodization of tungsten. The highest degradation efficiency (73%) was obtained for WO3 nanosheets synthesized in the presence of small amounts of hydrogen peroxide (0.05 M). For that nanostructure, the kinetic coefficient for diuron degradation was 133% higher than that for the other nanostructure (anodized in the presence of fluoride anions). These results have been explained by taking into account the different architecture and dimensions of the two WO3 nanostructures under study.
Interfacial Self-Assembly of Water-Soluble Cationic Porphyrins for the Reduction of Oxygen to Water
2012
Meet at the border: Assembly of the water-soluble cobalt tetrakis(N-methylpyridinium-4-yl)porphyrin [CoTMPyP]4+ at soft interfaces is enhanced and stabilized by its interfacial interaction with the lipophilic anion (C6F5)4B−. The supramolecular structure thus formed (see picture) provides excellent catalytic activity in the four-electron reduction of oxygen.