Overcoming Artifacts in Cyclic Voltammetry through the Use of Multiple Scan Rates and Potential Windows

A manganese substituted Anderson type polyoxometalate, [MnMo6O24]9-, tethered with an anthracene photosensitizer was prepared and used as catalyst for CO2 reduction. The polyoxometalate-photosensitizer hybrid complex, obtained by covalent attachment of the sensitizer to only one face of the planar polyoxometalate, was characterized by NMR, IR and mass spectroscopy. Cyclic voltammetry measurements show a catalytic response for the reduction of carbon dioxide, thereby suggesting catalysis at the manganese site on the open face of the polyoxometalate. Controlled potentiometric electrolysis showed the reduction of CO2 to CO with a TOF of ~15 sec-1. Further photochemical reactions showed that the polyoxometalate-anthracene hybrid complex was active for the reduction of CO2 to yield formic acid and/or CO in varying amounts dependent on the reducing agent used. Control experiments showed that the attachment of the photosensitizer to [MnMo6O24]9- is necessary for photocatalysis.<div> </div>

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Endgroup and Sidechain Functionalization of Surface-Initiated ROMP Thin Films: Progress Towards ROMP-Based Molecular Wires

10.26434/chemrxiv.5954518 ◽

2018 ◽

Author(s):

Nicholas Marshall

Keyword(s):

Thin Films ◽

Contact Angle ◽

Cyclic Voltammetry ◽

Polymer Films ◽

Conjugated Polymer ◽

Ring Opening ◽

Molecular Wires ◽

Metathesis Polymerization ◽

Cross Metathesis ◽

Active Ester

A set of experiments in surface-initiated ring-opening metathesis polymerization, including end-functionalization of growing brushes and contact angle/cyclic voltammetry measurements. We report preparation and CV of two different conjugated polymer films, and several endgroup and sidechain functionalization experiments using cross-metathesis and active ester substitution.

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Exploration of Bis(Arylimidazole) Iridium Picolinate Complexes

10.26434/chemrxiv.5331460.v1 ◽

2017 ◽

Cited By ~ 1

Author(s):

Aron Huckaba ◽

sadig aghazada ◽

iwan zimmermann ◽

giulia grancini ◽

natalia gasilova ◽

...

Keyword(s):

Cyclic Voltammetry ◽

Photophysical Properties ◽

Structure Property ◽

Aryl Group ◽

Ligand Modification ◽

Property Relationship ◽

Structure Property Relationship

The straightforward synthesis and photophysical properties of a new series of heteroleptic Iridium (III) bis(2-arylimidazole) picolinate complexes is reported. Each complex has been characterized by NMR, UV-Vis, cyclic voltammetry, and the emissive properties of each is described. By systematically modifying first the cyclometallating aryl group on the arylimidazole ligand and then the picolinate ligand, the ramifications of ligand modification in these complexes was better understood through the construction of a structure-property relationship.

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Exploration of Bis(Arylimidazole) Iridium Picolinate Complexes

10.26434/chemrxiv.5331460 ◽

2017 ◽

Author(s):

Aron Huckaba ◽

sadig aghazada ◽

iwan zimmermann ◽

giulia grancini ◽

natalia gasilova ◽

...

Keyword(s):

Cyclic Voltammetry ◽

Photophysical Properties ◽

Structure Property ◽

Aryl Group ◽

Ligand Modification ◽

Property Relationship ◽

Structure Property Relationship

The straightforward synthesis and photophysical properties of a new series of heteroleptic Iridium (III) bis(2-arylimidazole) picolinate complexes is reported. Each complex has been characterized by NMR, UV-Vis, cyclic voltammetry, and the emissive properties of each is described. By systematically modifying first the cyclometallating aryl group on the arylimidazole ligand and then the picolinate ligand, the ramifications of ligand modification in these complexes was better understood through the construction of a structure-property relationship.

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Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes

10.26434/chemrxiv.8014715.v1 ◽

2019 ◽

Author(s):

Georg Dewald ◽

Saneyuki Ohno ◽

Marvin Kraft ◽

Raimund Koerver ◽

Paul Till ◽

...

Keyword(s):

Cyclic Voltammetry ◽

Solid State ◽

Oxidative Stability ◽

Photoelectron Spectroscopy ◽

Solid Electrolytes ◽

Stability Limit ◽

Lithium Ion ◽

High Energy ◽

Redox Activity ◽

Solid State Batteries

All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use stepwisecyclic voltammetry to obtain information on the practical oxidative stability limit of Li10GeP2S12, a Li2S‑P2S5glass, as well as the argyrodite Li6PS5Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The stepwise cyclic voltammetryapproach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes.

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Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes

10.26434/chemrxiv.8014715 ◽

2019 ◽

Author(s):

Georg Dewald ◽

Saneyuki Ohno ◽

Marvin Kraft ◽

Raimund Koerver ◽

Paul Till ◽

...

Keyword(s):

Cyclic Voltammetry ◽

Solid State ◽

Oxidative Stability ◽

Photoelectron Spectroscopy ◽

Solid Electrolytes ◽

Stability Limit ◽

Lithium Ion ◽

High Energy ◽

Redox Activity ◽

Solid State Batteries

All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use stepwisecyclic voltammetry to obtain information on the practical oxidative stability limit of Li10GeP2S12, a Li2S‑P2S5glass, as well as the argyrodite Li6PS5Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The stepwise cyclic voltammetryapproach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes.

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Solar Exfoliated Graphene Oxide: A Platform for Electrochemical Sensing of Epinephrine

Current Analytical Chemistry ◽

10.2174/1573411015666190104110928 ◽

2020 ◽

Vol 16 (4) ◽

pp. 393-403 ◽

Cited By ~ 1

Author(s):

Renjini Sadhana ◽

Pinky Abraham ◽

Anithakumary Vidyadharan

Keyword(s):

Cyclic Voltammetry ◽

Graphene Oxide ◽

Glassy Carbon Electrode ◽

Glassy Carbon ◽

Simultaneous Detection ◽

Differential Pulse ◽

Carbon Electrode ◽

Modified Glassy Carbon Electrode ◽

Reduced Graphene ◽

Pulse Voltammetry

Introduction: In this study, solar exfoliated graphite oxide modified glassy carbon electrode was used for the anodic oxidation of epinephrine in a phosphate buffer medium at pH7. The modified electrode showed fast response and sensitivity towards Epinephrine Molecule (EP). The electrode was characterized electrochemically through Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Area of the electrode enhanced three times during modification and studies reveal that the oxidation process of EP occurs by an adsorption controlled process involving two electrons. The results showed a detection limit of 0.50 ± 0.01μM with a linear range up to 100 μM. The rate constant calculated for the electron transfer reaction is 1.35 s-1. The electrode was effective for simultaneous detection of EP in the presence of Ascorbic Acid (AA) and Uric Acid (UA) with well-resolved signals. The sensitivity, selectivity and stability of the sensor were also confirmed. Methods: Glassy carbon electrode modified by reduced graphene oxide was used for the detection and quantification of epinephrine using cyclic voltammetry and differential pulse voltammetry. Results: The results showed an enhancement in the electrocatalytic oxidation of epinephrine due to the increase in the effective surface area of the modified electrode. The anodic transfer coefficient, detection limit and electron transfer rate constant of the reaction were also calculated. Conclusion: The paper reports the determination of epinephrine using reduced graphene oxide modified glassy carbon electrode through CV and DPV. The sensor exhibited excellent reproducibility and repeatability for the detection of epinephrine and also its simultaneous detection of ascorbic acid and uric acid, which coexist in the biological system.

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Hydrophobic Ferrocene Derivatives as Potential Standards in Electrochemistry

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19970185 ◽

1997 ◽

Vol 62 (2) ◽

pp. 185-198 ◽

Cited By ~ 6

Author(s):

Jaroslav Podlaha ◽

Petr Štěpnička ◽

Róbert Gyepes ◽

Vladimír Mareček ◽

Alexander Lhotský ◽

...

Keyword(s):

Surface Tension ◽

Cyclic Voltammetry ◽

Redox Potential ◽

Diffusion Coefficients ◽

Carbon Electrodes ◽

X Ray Diffraction ◽

Ferrocene Derivatives ◽

X Ray ◽

Special Cases ◽

As Solubility

Ferrocene (FcH) derivatives monosubstituted by palmitoyl (1), hexadecyl (2), 1-adamantoyl (3) or 1-adamantylmethyl (4) groups were sythesized and characterized by NMR, mass and 57Fe Mossbauer spectroscopy. The structure of 1-adamantoylferrocene was determined by single-crystal X-ray diffraction. Cyclic voltammetry on gold and glass-like carbon electrodes demonstrated that the compounds can serve as electrochemical standards for special cases since their ferrocene/ferricinium redox potential remains stable and reversible, while the properties such as solubility, diffusion coefficients and surface tension are strongly solvent-dependent.

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