Products Of Electrochemical Oxidation Research Articles

Corrosion and oxidation behaviors of CoAlTiWTa RHEA coating on Inconel 718 superalloy prepared by laser cladding

CoAlTiWTa refractory high-entropy alloy (RHEA) coating was prepared on Inconel 718 superalloy by pulsed laser cladding. Corrosion behavior in 3.5 wt% NaCl solution at room temperature and oxidation behavior at 600 ℃ of the coating were systematically investigated. The electrochemical performance, surface morphology, and corrosion and oxidation products were carefully characterized. The results show that the RHEA coating has a higher corrosion potential, smaller corrosion current, higher resistance value, and a more obvious passivation effect. Duplex-layer oxide film composed of an internal Al2O3-TiO2 layer and an external Co oxide layer is formed on the RHEA coating, improving high-temperature oxidation resistance.

Electrochemical oxidation diminished toxicity of zearalenone significantly, while reduction increased.

Zearalenone (ZEN), one of the most common mycotoxins in cereals, poses a severe health risk to humans. In this study, electrochemical oxidation and reduction degraded ZEN in solution completely within 8min and 20min. The structure of ZEN products was elucidated by mass spectrometry (MS), and their toxicity was evaluated by ECOSAR software and cytotoxicity assay. From simulation, electrochemical oxidation products had lower acute and chronic toxicity, and the product at 9.0V is not harmful (LC50/EC50greater than100mg/L, ChVgreater than10mg/L). CCK-8 assay further confirmed their less cytotoxicity. To our surprise, LC50, EC50, and ChVs of all electrochemical reduction products were lower than 1mg/L, and cell viabilities were less than ZEN, meaning the higher toxicity of electrochemical reduction products. On this Basis, electrochemical oxidation was applied in ZEN contaminated wheat with a degradation rate of 92.32±2.37%, indicating its potential to degrade ZEN practically.

Electrochemical Oxidation of 4-(Hydroxymethyl)Benzoic Acid

We have investigated the electrochemical oxidation of 4-(hydroxymethyl)benzoic acid (4-HMBA) on different metallic working electrodes in alkaline electrolytes, including gold (Au), nickel (Ni), and platinum (Pt) metal. Au shows the lowest onset potential for catalyzing the electrooxidation of 4-HMBA among the three metals in base, whereas Pt does not catalyze the electrooxidation of 4-HMBA under alkaline conditions. The products of electrochemical oxidation of 4-HMBA catalyzed on Au working electrode are 4-carboxybenzaldehyde and terephthalic acid analyzed by high-performance liquid chromatography. The electrodeposited Au nanostructures on indium tin oxide (ITO)-coated glass is further utilized as the working electrode and catalyst for the 4-HMBA electrooxidation by introducing the plasmonic effects of the Au nanostructures. With the broad absorption of the Au nanostructures anchored on the ITO substrate in the visible and near-infrared range, we show that they could enhance the electrochemical oxidation of 4-HMBA under green and red LED light illuminations. The plasmonic effects of the Au nanostructures are proposed to contribute to the enhancement of the reaction and the photothermal effect is excluded based on electrolyte-temperature-dependent measurements. A possible reaction mechanism is proposed for the electrochemical oxidation of 4-HMBA on Au working electrodes in an alkaline electrolyte. Ongoing work focuses on investigating the electrochemical oxidation of electronically unique aromatic substituents of 4-HMBA and the plasmonic effects from the Au nanostructure electrodes in assisting other electrochemical reactions.

New Type of Neutral Binuclear Spin‐Crossover Complex of Iron(III) with Twist of Two Disulfide Bridges as a Product of Electrochemical Oxidation of [FeIII(5Cl‐thsa)2]− Anions

AbstractAs a result of the electrochemical oxidation process, the [FeIII(5Cl‐thsa)2]− spin‐crossover (SCO) anion with N2S2O2 coordination sphere transforms into N4O2‐coordinated FeIII SCO neutral binuclear complex 2 with twist of two disulfide bridges. Each dimeric complex is a binuclear double‐stranded helicate with similar chirality of both Fe centers. The crystal structure of the complex 2 ⋅ 3H2O at 100 K has a monoclinic C2/c space group and contains large cavities (about 21.5 % of the unit cell volume) half‐filled by 3 water molecules per one dimer. The N4O2 coordination of iron(III) with two oxygen atoms (−O−) of phenoxy groups, two imine‐type (−Nim=) nitrogen atoms of azomethine groups, one amidrazone‐type (=NamidH) nitrogen atom and one ionized terminal group (−NionizH) of nitrogen has not been observed in CCDC so far. The oxidation state of the iron atoms in the dimeric complex was confirmed by 57Fe Mössbauer spectroscopy on 90 % enriched 57Fe sample. Mössbauer spectra and dc magnetic measurements demonstrated the partial HS‐HS→LS‐LS SCO in the 185–225 K temperature range. The details of the structure of complex 2 and the features of its magnetic properties were refined by theoretical analysis based on DFT calculations. The B3LYP* functional correctly predicting the energy of the spin‐crossover process was revealed.

Ultrasensitive Detection of Carcinoembryonic Antigen by Chitosan/Polythiophene/CdTe Electrochemical Biosensor.

A facile method for the in situ fabrication of chitosan/polythiophene/CdTe (CS/PTh/CdTe) nanocomposite has been developed. It was then connected with anti-CEA (Ab), which was evoked for the electrochemical detection of carcinoembryonic antigen (CEA, Ag) within K4Fe(CN)6. The results indicate that CS/PTh/CdTe/GCE has a high selectivity for the detection of CEA with a wide linear range of 0.0001-10000 ng/mL and excellent sensitivity with a low detection limit of 40 fg/mL. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and in situ FT-IR spectra are evoked to study the mechanism of detection of CEA via CS/PTh/CdTe/GCE. The high sensitivity of the electrochemical sensor is due to the fact that the electrochemical oxidation products of K4Fe(CN)6 can directly oxidize CdTe from a low energy state to a high energy state (CdTe)*, making CdTe more prone to be oxidized and facilitate electron transfer. The developed electrochemical biosensor can be used for the detection of real samples, providing a precise method for the detection of CEA with potential application in the clinical detection of tumors.

Plasmon-enhanced electrochemical oxidation of 4-(hydroxymethyl)benzoic acid.

Plasmon-mediated electrocatalysis based on plasmonic gold nanoparticles (Au NPs) has emerged as a promising approach to facilitate electrochemical reactions with the introduction of light to excite the plasmonic electrodes. We have investigated the electrochemical oxidation of 4-(hydroxymethyl)benzoic acid (4-HMBA) on gold (Au), nickel (Ni), and platinum (Pt) metal working electrodes in alkaline electrolytes. Au has the lowest onset potential for catalyzing the electrooxidation of 4-HMBA among the three metals in base, whereas Pt does not catalyze the electrooxidation of 4-HMBA under alkaline conditions, although it is conventionally a good electrocatalyst for alcohol oxidation. Both 4-carboxybenzaldehyde and terephthalic acid are detected as the products of electrochemical oxidation of 4-HMBA on the Au working electrode by high-performance liquid chromatography . The electrodeposited Au NPs on indium tin oxide (ITO)-coated glass is further utilized as the working electrode for the 4-HMBA electrooxidation. With its broad absorption in the visible and near-infrared range, we show that the Au NPs on the ITO electrode could enhance the electrochemical oxidation of 4-HMBA under green and red LED light illuminations (505 and 625nm). A possible reaction mechanism is proposed for the electrochemical oxidation of 4-HMBA on Au working electrodes in an alkaline electrolyte.

Thiogenistein-Antioxidant Chemistry, Antitumor Activity, and Structure Elucidation of New Oxidation Products.

Isoflavonoids such as genistein (GE) are well known antioxidants. The predictive biological activity of structurally new compounds such as thiogenistein (TGE)–a new analogue of GE–becomes an interesting way to design new drug candidates with promising properties. Two oxidation strategies were used to characterize TGE oxidation products: the first in solution and the second on the 2D surface of the Au electrode as a self-assembling TGE monolayer. The structure elucidation of products generated by different oxidation strategies was performed. The electrospray ionization mass spectrometry (ESI-MS) was used for identifying the product of electrochemical and hydrogen peroxide oxidation in the solution. Fourier transform infrared spectroscopy (FT-IR) with the ATR mode was used to identify a product after hydrogen peroxide treatment of TGE on the 2D surface. The density functional theory was used to support the experimental results for the estimation of antioxidant activity of TGE as well as for the molecular modeling of oxidation products. The biological studies were performed simultaneously to assess the suitability of TGE for antioxidant and antitumor properties. It was found that TGE was characterized by a high cytotoxic activity toward human breast cancer cells. The research was also carried out on mice macrophages, disclosing that TGE neutralized the production of the LPS-induced reactive oxygen species (ROS) and exhibits ABTS (2,2′-azino-bis-3-(ethylbenzothiazoline-6-sulphonic acid) radical scavenging ability. In the presented study, we identified the main oxidation products of TGE generated under different environmental conditions. The electroactive centers of TGE were identified and its oxidation mechanisms were proposed. TGE redox properties can be related to its various pharmacological activities. Our new thiolated analogue of genistein neutralizes the LPS-induced ROS production better than GE. Additionally, TGE shows a high cytotoxic activity against human breast cancer cells. The viability of MCF-7 (estrogen-positive cells) drops two times after a 72-h incubation with 12.5 μM TGE (viability 53.86%) compared to genistein (viability 94.46%).

Confined electrochemiluminescence imaging microarray for high-throughput biosensing of single cell-released dopamine

The quantitative detection of single cell secretions is always limited by their accurate collection and the heterogeneity of different cells. In this work, a confined electrochemiluminescence (ECL) imaging microarray (CEIM) chip was designed to capture single or a few cells in each cylindrical microwell for high-throughput quantitation of cell-secreted dopamine (DA). The ITO surface at the bottom of microwells was functionalized with the film of DA aptamer modified coreactant-embedded polymer dots (Pdots), which endowed the chip with the abilities to both in situ recognize the target DA secreted from the cells and emit the ECL signal for responding the secreted target without need of any additional coreactant. At the applied potential of +1.4 V, the Pdots in the film emitted strong ECL signal, which could be quenched by the electrochemical oxidation product of DA in individual microwell for sensitive detection of single cell-released DA. The practicability of the proposed CEIM chip along with the ECL imaging and biosensing strategy was demonstrated by evaluating the amounts of single cell-released DA in different microwells under hypoxia stimulation. This protocol revealed the heterogeneity of cell secretion, and could be extended for quantitation of other secretions from different kinds of single cells.

A new approach in deep desulfurization of model fuel through integration of electrochemical oxidation and liquid-liquid extraction in a biphasic system

An extraction-electrooxidation (E-EODS) system is introduced for the removal of dibenzothiophene (DBT) from model fuel (DBT in n-hexane). The process is run in an electrochemical cell as a batch reactor, where, the model fuel is in contact with an appropriate immiscible polar solvent composed of acetonitrile and water (MeCN-water, 90:10% v/v) that serves as both the extraction solvent and electrochemical medium. The electrochemical oxidation of DBT, which is extracted into the MeCN-water phase, enhances the continuous removal of DBT from the model fuel phase. The effects of the composition of the extraction solvent, applied potential and the process time on DBT removal efficiency are assessed. The results indicate that with the selection of the MeCN-water, 90:10 v/v in a 1:1 ratio respect to the model fuel, this extraction method yields about 100% extraction efficiency within 5 h, at 25 °C at 2.9 V and atmospheric pressure as determined by HPLC technique. Cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy, and gas chromatography-mass spectrometry (GC–MS) techniques are applied to identify the electrochemical oxidation products of DBT. The electrochemical oxidation-derived extraction process through this method is innovative and feasible for deep desulfurization of liquid fossil fuels.

Preparation of Ti-based Yb-doped SnO2–RuO2 electrode and electrochemical oxidation treatment of coking wastewater

In this study, the Ti/SnO2–RuO2 electrodes with different Yb contents were prepared by sol–gel method and thermal decomposition method, and the surface morphology and crystal structure of the electrodes were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD), the electrochemical properties of the electrodes were tested by linear sweep voltammetry (LSV) and cyclic voltammetry (CV). The electrochemical oxidation device was constructed with Yb-doped Ti/SnO2–RuO2 electrode as the anode and titanium plate as the cathode, and the electrochemical oxidation effect and product changes of the anode on coking wastewater were investigated. The results show that the surface of the electrode is flat with high crystallinity of SnO2 and RuO2 crystals at 1.5% Yb doping, and the LSV and CV curves indicate that the Yb doping of 1.5% increases the oxygen precipitation potential and electrocatalytic oxidation activity of the electrode. When the electrode with Yb doping of 1.5% is the anode with current density of 10 mA/cm2 electrochemical oxidation time of 30 min, the electrode can remove chemical oxygen demand (COD) up to 85.06%, total organic carbon (TOC) up to 60.59% and UV254 from 1.594 to 0.507 for coking wastewater. Gas chromatography (GC–MS), UV–vis and three-dimensional fluorescence results of coking wastewater before and after treatment show that large toxic substances in coking wastewater are degraded to low toxic organic substances, and most soluble organic substances are degraded and transformed. This study provides the possibility of basic research for the engineering practice of electrochemical oxidation for the treatment of coking wastewater.

Electrochemically oxidized 15-crown-5 substituted thiophene and host-guest interaction with new psychoactive substances

The aim of this work is to develop an impedimetric sensor using the principle of host-guest interaction for the detection of new psychoactive substances (NPSs). Synthesized 4′-(N-3-thiophenecarboxamido)benzo-15-crown-5 (TH3CA4AB15C5) was electrochemically deposited on the surface of a platinum disc electrode using cyclic voltammetry. Spectroscopic (infrared and NMR spectroscopy) and electrochemical impedance spectroscopy (EIS) studies were applied to confirm the structure of the polymeric film deposited onto the electrode surface and to evaluate its affinity towards 2-aminoindane (AI), 2-(methylamino)-1-phenylbutan-1-one (buphedrone, MABP) and 3′,4′-methylenedioxy-α-pyrrolidinopropiophenone (MDPPP). These studies showed that the ease of formation hydrogen bonds between the product of electrochemical oxidation (TH3CA4AB15C5) and the above-mentioned analytes is the dominant factor for obtaining a useful analytical signal. The changes in the resistance to charge transfer obtained during the EIS measurements allowed: i) to separately measure both the synthetic cathinones (MABP, MDPPP) and AI in the concentration range 1.99 x 10 –5 – 1.22 x 10– 3 M; ii) to quantify AI at levels of (1.6 – 3.0) x 10–4 M in the presence of various representatives from the NPS family.

Al2O3 microparticles immobilized on glassy‑carbon electrode as catalytic sites for the electrochemical oxidation and high detectability of naproxen: Experimental and simulation insights

This work demonstrates that Al2O3 microparticles immobilized on a glassy‑carbon electrode (GCE) anticipate the electrochemical oxidation of naproxen in 150 mV and increases its oxidation current, resulting in a highly sensitive sensor. Considering their non-conducting nature, we suggest that Al2O3 microparticles act as adsorption sites that alter the electrochemical oxidation pathway of naproxen by adsorbing its intermediate(s) and facilitating the electron transfer at the GCE surface. Interestingly, the voltammetric results obtained for ibuprofen (presents similar chemical structure and electrochemical oxidation mechanism) indicated the same facilitated electron transfer that suggests that the interaction between naproxen (or ibuprofen) with Al2O3 microparticles occurs via the carboxylic group, which is removed after the first electron transfer according to the proposed mechanism. Molecular dynamics simulations showed stronger interaction of naproxen than ibuprofen with alumina sites which may explain the respective facilitated electron transfer. Moreover, a stronger interaction of a major electrochemical oxidation product of naproxen with alumina was confirmed by simulation and explains the electrode fouling occurred when more positive potentials (+1.4 V instead of +1.0 V vs. Ag/AgCl/KClsat) were applied for the naproxen amperometric detection. The alumina-modified GCE surface presented a detection limit of 12 nmol L−1 with a linear range between 50 and 500 nmol L−1 for naproxen determination (Edet = +1.0 V). These sensing characteristics are superior in comparison with electrodes modified with carbon nanotubes and their composites. Hence, a simpler protocol for electrode modification using a non-conducting material can provide a highly sensitive sensor for naproxen due to its catalytic properties facilitating the electron transfer between naproxen (or ibuprofen) and GCE.

Electrochemical oxidation of synthetic amino-substituted benzamides with potential antioxidant activity

Amino-substituted benzamide derivatives are very attractive compounds due to their capacity to act as powerful antioxidants by scavenging free radicals. Knowledge on electrochemical oxidation mechanisms plays an important role in understanding the free radical scavenging activity of antioxidants. In this paper, the electrochemical oxidation of four amino-substituted derivatives [N-(4-aminophenyl)-2-hydroxybenzamide (1), N-(4-aminophenyl)-2-hydroxy-4-methoxybenzamide (2), N-(4-aminophenyl)-2-methoxybenzamide (3), N-(4-aminophenyl)-3,4,5-trihydroxybenzamide (4)] in an aqueous buffer solution was studied by means of cyclic and square-wave voltammetry, and probable reaction mechanisms have been proposed. In compounds 1–3, the primary amino group was found to be the main electroactive centre undergoing a complex, pH-dependent oxidation process with the transfer of two electrons and two protons. This reaction occurs in one step or in two separate steps, depending on the pH of the medium. A possible explanation for this electrochemical behaviour is discussed. The final products of initial electrochemical oxidation of amino-substituted benzamides 1–3 are quinonediimine derivatives that undergo further chemical transformation into electroactive forms. Oxidation of compound 4 proceeds through two sequential reactions; the first anodic reaction is the oxidation of the trihydroxyphenyl group to the corresponding o-quinone, followed by the oxidation of a primary amino group. Considering the oxidation potentials, and bearing in mind that lower/less positive potential implies better radical scavenging activity, the order of antioxidant activity of the here studied amino-substituted benzamides is: 4 >2 >1 >3.

A label-free impedimetric immunosensor based on covalent immobilization of anti-E. Coli antibody via a copper-catalyzed azide-alkyne cycloaddition reaction.

In this article, an original method is proposed for address and covalent immobilization of anti-E. coli antibodies on a screen-printed electrode (SPE). The method is based on a copper-catalyzed "click" reaction between a polyvinylbenzylazide (PVBA) film electrochemically deposited on the electrode surface and acetylene fragments of propargyl-N-hydroxysuccinimide ester. The products of electrochemical oxidation of copper particles incorporated in the polymer film on the electrode were first used for catalysis of the click reaction. This approach allowed us to reduce the immobilization time from a few hours for conventional methods to just 30min, and to prevent denaturation of the immunoreceptor. The modified electrodes were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Based on the results obtained, a label-free impedimetric immunosensor for E. coli detection was developed. The detection limit of the immunosensor was estimated as 6.3CFU/ml, with a linear range of 103-106CFU/ml. The immunosensor demonstrated good stability during 30days of storage in phosphate buffer solution (PBS, pH7) and selectivity toward excess Staphylococcus aureus bacteria.

Electrochemical Oxidation Products of Piperazine as Corrosion Inhibitor for HP13Cr Steel in 20% HCl Solution

Electrochemical Oxidation Products of Piperazine as Corrosion Inhibitor for HP13Cr Steel in 20% HCl Solution

Electrochemical properties of arylsilanes

In the past, the electrochemical properties of organosilicon compounds were investigated for both fundamental reasons and synthesis purposes. Little is, however, known about the electrochemical behaviour of hydrogen-bearing arylsilanes. Here, we throw light on the electrochemical properties of 11 arylsilanes compounds, 2 of them synthesized for the first time. The oxidation potentials are found to depend on both the nature and number of the aryl groups. Based on these findings it was possible to establish some variation trends that match the expected structure–property correlations. Furthermore, we present first insights into the electrochemical reaction kinetics behind and identify several soluble electrochemical oxidation products.

Investigation of the electrochemical oxidation of 2,3'-bisindolylmethanes in positive-ion electrospray ionization mass spectrometry.

Electrochemical reactions in electrospray may affect the electrospray ionization mass spectrometry (ESI-MS) detection of the analytes. During ESI-MS analysis of 2,3′-bisindolylmethanes in the positive-ion mode, when methanol or acetonitrile was used as the solvent, electrochemical oxidation products as the dehydro and radical cations were observed. Lower sample introduction rates tended to result in a higher oxidation ratio of 2,3′-bisindolylmethanes. The ESI-MS experiments of 2,3′-bisindolylmethanes in different acetonitrile/methanol solvent mixtures indicated that abundant H+, Na+ or K+ would facilitate the adduct formation process, and otherwise electrochemical oxidation dominated the ionization process. Additionally, when dichloromethane was used as the solvent, [M − 3H]+, [M − 2H]+˙ and [M − 3H + O]+ ions are the predominant ions, and the experimental results revealed that the dehydrogenation and oxidative dehydrogenation reactions of 2,3′-bisindolylmethanes in dichloromethane are electrochemical reactions.

Transition Metal Dissolution in State-of-the-Art and Next Generation Li-Ion Batteries Studied By Spatially Resolved Operando X-Ray Absorption Spectroscopy

High energy Li-Ion batteries rely on the pairing of a transition metal oxide cathode with a graphite anode. Pushing the upper cut-off voltage and state of charge (SOC) to higher values, the cycle-life of the battery is drastically reduced. Besides electrochemical electrolyte oxidation leading to poor coulombic efficiencies and a large growth of cell impedance, leaching of transition metal ions from the cathode active materials is one of the major obstacles to increase the power density of the cell without change of active materials. While the capacity loss which can be ascribed to the overall loss of active material is minor, cell aging is largely aggravated by liberated transition metal ions present in the electrolyte, as they diffuse through the separator and deposit on the graphite anode due to its low potential. A severe impedance growth of the anode and loss of active lithium by chemical delithiation of the graphite has been observed by many studies. Especially for manganese, the amount of active lithium loss has been found to be a multifold higher than the total amount of manganese ions present in the electrolyte and deposited onto the graphite anode, indicating a catalytic role of transition metal ions on active lithium loss (1). Comparisons of the transition metal leaching behavior for different cathode active materials is missing so far, as studies vary widely in test procedures (potential range, SOC) and environment (electrolyte and temperature). We herein present operando analysis of the intrinsic stability of several cathode active materials upon charge to high SOC and potential with our unique spectroscopic cell enabling spatially resolved operando X-ray absorption spectroscopy, monitoring the concentration and oxidation state of transition metals in the electrolyte and in the graphite anode (2, 3). Aside layered mixed transition metal oxide materials (Li1+w[NixCoyMnz]1-xO2) also the spinel structure is tested to better understand the effect of crystal destabilization at high SOC. The formerly standard layered oxide NCM111 (x=y=z=0.33) was already studied earlier, focusing on manganese dissolution (3). In this talk we present time and potential resolved analysis of all transition metals released from NCM111 (see Fig. 1) in comparison to a nickel-rich NCM811 (x=0.8, y=z=0.1), a lithium- and manganese-rich layered oxide material (HE-NCM; w=0.17, x=0.22, y=0.12, z=0.66 (4)) and the high-voltage spinel LiNi0.5Mn1.5O4, (LNMO). This data allows conclusions on the extent of the two major causes for transition metal leaching from oxide based cathode materials: chemical decomposition induced by protic electrochemical electrolyte oxidation products (5) and crystal lattice destabilization of layered transition metal oxides caused by high degrees of delithiation (high SOC). References J. A. Gilbert, I. A. Shkrob and D. P. Abraham, Journal of The Electrochemical Society, 164, A389 (2017). Y. Gorlin, A. Siebel, M. Piana, T. Huthwelker, H. Jha, G. Monsch, F. Kraus, H. A. Gasteiger and M. Tromp, Journal of the Electrochemical Society, 162, A1146 (2015).J. Wandt, A. Freiberg, R. Thomas, Y. Gorlin, A. Siebel, R. Jung, H. A. Gasteiger and M. Tromp, J. Mater. Chem. A, 4, 18300 (2016). B. Strehle, K. Kleiner, R. Jung, F. Chesneau, M. Mendez, H. A. Gasteiger and M. Piana, Journal of The Electrochemical Society, 164, A400 (2017). M. Metzger, B. Strehle, S. Solchenbach and H. A. Gasteiger, Journal of The Electrochemical Society, 163, A798 (2016). Acknowledgements Financial support for S. S. and B. S. by the BASF SE through its Research Network on Electrochemistry and Batteries is gratefully acknowledged. XAS data were gathered at the European Synchrotron Radiation Facility (ESRF) and SOLEIL Synchrotron (France).We are grateful to Dr. Debora Motta Meira at the ESRF, Grenoble (France) for providing assistance in using beamline BM 23 as well as Dr. Emiliano Fonda for assistance on the SAMBA beamline at SOLEIL Synchrotron. Fig. 1: Transition metal dissolution of an NCM111 (5.5 mAh/cm2)//C6 cell upon cycling in the conventional potential range (0-6.5 h: 60% SOC until ≈4.2 VLi) and upon high degrees of delithiation (7-11 h: ≈100% SOC until 5.1 VLi) measured in our operando XAS cell using glass fiber separators and standard LP57 electrolyte (1 M LiPF6 in EC:EMC [3:7]) at 25 °C. The concentration of transition metal ions within the graphite electrode (filled symbols) and in the electrolyte (hollow stars, shown as electrolyte share in the graphite pores [concentration measured in the separator multiplied by the porosity of the graphite anode]) is monitored operando. Figure 1

Electroorganic Oxidation of Pyridones

Electroorganic synthesis can be utilized as a green alternative in complex organic synthesis reactions for pharmaceutical compounds, mitigating or eliminating complex stoichiometric oxidants during organic synthesis. An electrochemical oxidation reaction can make a synthetic transformation more cost effective and more efficient when compared to traditional oxidation processes. Recently, literature has indicated that in waste water treatment applications, benzene and phenols are completely oxidized, resulting in CO2 formation, but interestingly also resulting in some partial oxidation products of quinones and catechols. Following a similar scheme to intentionally produce partial electrochemical oxidation products and oxidation intermediates can yield interesting new chemistries. In this work, we will focus on heterocyclic electrochemistry and their partial oxidations specifically for pyridones. Pyridones and pyridines are considered for their possible use in biological reactions or in mimicking bioorganic processes. Various electrochemical oxidations with pyridones as an organic substrate are being explored, specifically N-alkyl pyridones. Herein, focus will be on examining various cyclic voltammograms for different supporting electrolyte systems while comparing one and two electrochemical cell systems. Reaction rates and possible electrochemical mechanisms will be developed similarly to literature on electrochemical sensors. Furthermore, the electrochemical analysis will be derived and compared to the reaction products characterized by LC-MS.

A novel electroanalytical assay for sulfamethazine determination in food samples based on conducting polymer nanocomposite-modified electrodes

The toxicity of sulfa drugs has attracted great attention, and the reported electrochemical methods for sulfa drugs usually employ a high oxidation potential. In this work, a one-pot synthesized conducting polymer nanocomposite containing poly(3,4-ethylenedioxythiophene) (PEDOT) and MnO2 was cast on a screen-printed carbon electrode (SPCE), and the modified electrode showed superior electrochemical activity over a bare electrode for sulfamethazine (SMZ) determination. The SMZ detection was based on the electrochemical oxidation product, which showed an adsorptive property and exhibited a redox couple at 0.39V in pH 3 phosphate buffer solutions (PBS). The electrode surfaces were well characterized by the water contact angle technique, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and cyclic voltammetry. By the use of square wave voltammetry (SWV), a wide linear response to SMZ, from 1.0µM to 500μM, was obtained. The sensitivity and detection limits (S/N = 3) were 0.115μAμM−1 and 0.16μM, respectively. The proposed method and a reference high-performance liquid chromatographic method (HPLC) were applied for the determination of SMZ in two real samples using the standard addition method, and satisfactory recoveries and good agreement were obtained.