Electrochemical Method For Synthesis Research Articles

Progress of NiO-Based Anodes for High-Performance Li-Ion Batteries.

Rechargeable lithium-ion batteries (LIBs) are of great significance to the development of renewable energy. The traditional graphite anode is gradually unable to meet increasing demands for high energy density and power density due to its low theoretical capacity. NiO has gained considerable attention because of its high theoretical capacity, low toxicity, and stable chemical properties. This review summarizes the research progress of NiO-based nanomaterials in LIBs and centers on the electrochemical reaction mechanism, synthesis methods, and strategies for improving the electrochemical properties of NiO anodes. The results demonstrate that the electrochemical characteristics highly depend on the synthesis method, morphology, surface area, conductive substrate, etc. Compared with pure NiO, NiO-based composites including NiO/carbon-based materials and NiO/metal oxide often present higher capacity and cycle stability. Furthermore, challenges and future perspectives of NiO-based anodes are also discussed.

Electrochemical Synthesis Methods of Metal‐Organic Frameworks and Their Environmental Analysis Applications: A Review

AbstractMetal‐organic frameworks (MOFs) have been increasingly utilized in the field of modern environmental analysis. Among the various synthesis approaches of MOFs, electrochemical synthesis methods have attracted much attention due to the green advantages in the aspects of mild preparation and convenient control for improving the probability of MOFs’ continuous and large‐scale production. In this review, from theory to application, the mechanisms of different electrochemical synthesis methods for MOFs were summarized and emphasized. They provided theoretical guidance for synthesizing new MOFs and developing novel eco‐friendly electrochemical synthesis methods for MOFs’ application in environmental analysis. Moreover, the applications of MOFs in environmental analysis field in recent years were comprehensively illustrated and the advantages and disadvantages of electrochemical synthesis methods to prepare MOFs as environmental analytical nanomaterials were evaluated. Finally, some suggestions for the optimization of electrochemical synthesis methods for MOFs and their future opportunities in environmental analytical applications were proposed.

A simple salt mediated electrooxidative method for the synthesis of benzaldehydes from benzyl alcohols

A mild and efficient approach for the electrochemical conversion of benzyl alcohols to benzaldehydes is reported in homogeneous medium using Carbon/Stainless Steel electrodes and NaCl as mediator with H2SO4 as supporting electrolyte. To achieve excellent product conversion, optimization of the reaction condition with various parameters was carried out in a beaker type cell. In 2 F of current density and ambient temperature, benzyl alcohols electrochemically oxidized to benzaldehydes in 90% yield. The present work demonstrates a green and sustainable route for benzaldehydes preparation and the superiority of electrochemical method for organic synthesis.

Electrochemical Method of Copper Powder Synthesis on Rotating Electrode in the Presence of Surfactants

Electrochemical Method of Copper Powder Synthesis on Rotating Electrode in the Presence of Surfactants

ELECTROREDUCTION OF DITUNGSTATE AND CARBONATE ANIONS IN CHLORIDE MELT

Electrocatalysis is one of the actively developing fields of application of tungsten carbides. For the synthesis of catalytically active carbides (materials with a large specific surface area, small particle size and structural defects) a large number of different technologies are being developed in the world. The method of high-temperature electrochemical synthesis is promising one. For its successful realization, it is necessary to study in detail the electrochemical behavior of each carbide component (tungsten and carbon) and the features of their partial and joint discharge. The aim of this paper is a voltammetric study of the partial and joint electroreduction of Na2W2O7 and Li2CO3 in molten NaCl–KCl electrolyte under CO2 pressure at a temperature of 750 °C.
 As a result of research, it was found that in the system Na,K|Cl–Na2W2O7–Li2CO3–CO2 joint reduction of tungsten carbide synthesis components occurs from lithium complexes of tungstate (LixWO4)2-x and carbonate- (LixCO3)2-x anions at potentials -1.65 – -1.8 V. Introduction of СО2 into the system (creation of its excess pressure in the cell) is necessary for the binding of oxide anions O2-, released during the discharge of anionic complexes, into a carbonate complex. The released oxide anion in the near-electrode layer inhibits the cathodic process. Also, a necessary condition for the sustainability production of tungsten monocarbide WC is the presence of free carbon, which is formed during the decomposition of CO2.
 Nanosized composites of tungsten carbides with free carbon WC/C (5 wt%) were obtained by potentiostatic electrolysis at a potential of -1.8 V as a cathode product. The properties of the obtained compounds were analyzed by XRD, SEM, BET, and Raman spectroscopy. Tungsten carbide has a particle size of ~ 10 nm and consists of hollow spherical structures. The synthesized composite is mesoporous material with a specific surface area of ~ 140 m2/g.
 The properties of the synthesized compo­site, namely: structural defects, the presence of free carbon, spherical morphology, nanometer size and high specific surface area, make it possible to use it as an effective electrocatalyst, for example, in the reaction of hydrogen evolution in acidic aqueous solutions.

Novel fabrication strategy of nanostructured NiCo-LDHs monolithic supercapacitor electrodes via inducing electrochemical in situ growth on etched nickel foams

Development of electrode materials with high electrochemical charge storage capabilities through cost-effective methods has attracted intensive attention from researchers. Herein, a low-cost and scaled-up method for electrochemical synthesis of monolithic electrodes is presented. Nickel foam (NF) was chemically etched using the transition metal (NiCo-based) nitrate solutions with different ratios of Ni and Co. After being rinsed and dried, the etched NF was used as anode in an alkaline solution and a Pt mesh was utilized as cathode. Shortly after a constant voltage was applied to the two-electrode system, NiCo-based layered double hydroxides (NiCo-LDHs) were found to be self-grown on the NF with an ultra-fast rate. The in situ grown NiCo-LDHs were composed of hierarchical nanosheets with rough and porous surfaces, and had a high specific area. The monolithic Ni1Co2/NF electrode exhibited the best electrochemical performance with a high specific capacity of 3.01 C cm−2 at 1 mA cm−2. A hybrid supercapacitor was assembled using the Ni1Co2/NF as positive electrode and activated carbon as negative electrode. It exhibited a high energy density of 97.4 μWh cm−2 at a power density of 800.5 μW cm−2, and retained 85.0% of initial capacity after 5000 cycles.

Synthesis and characterization of an electrochromic copolymer based on 9, 10-di (furan-2-yl)anthracene and 3,4-ethylenedioxythiophene.

In this study, a new copolymer, which is a combination of two chemical structure (9,10-di(furan-2-yl)anthracene and 3,4-ethylenedioxythiophene was synthesized via electrochemical synthesis methods in the electrolyte medium of 0.1 M TBAPF6/ACN solution. PEDOT homopolymer was also electrosynthesized for comparator experiments of the polymer formations in the same medium. The characterizations of polymers were achieved with general optical and electrochemical characterization techniques. The corresponding electrochromic copolymer shows blue and lilac color in its neutral and oxidized states, respectively. The copolymer has an optical band gap of 1.65 eV and 24% optical contrast at 500 nm with a high coloration efficiency (170 cm2 /C) and a fast switching time (1.0 s).

Oxidant-free C-H sulfonylation of enamides: Electrochemical synthesis of β-amidovinyl and carbonyl sulfones from sulfonyl hydrazide and enamides

A mild, practical, eco-friendly and environmentally friendly electrochemical synthesis method of β-aminovinyl sulfone and carbonyl sulfones from sulfonyl hydrazide and enamides has been developed. This transformation only requires electrolytes and solvent, thus avoids transition metal catalysts, stoichiometric oxidant and base. Two different types of sulfone derivatives can be obtained only by changing the reaction solvent. This transformation also features mild conditions (room temperature, air), broad substrate scopes, and excellent stereoselectivities in mild to good yield.

Electrolytical Carbon Nanostructures from Molten Salts: Synthesis and Properties

Carbon nanomaterials (CNMs) occupy a special place in nanoscience owing to exceptional thermal, electrical, chemical and mechanical properties. They are used in various areas of modern technologies: super-strong composite materials, supercapacitors, smart sensors, targeted delivery drugs, catalyst carriers, field emission devices, quantum wires, paints, for energy storing and conversion, for gas storing, in nanoelectronics, etc. Therefore, a great attention is given all over the world to the development of novel efficient method for the fabrication of CNMs, comprehensive investigation of their properties, and search for new applications. Today there are many methods for the synthesis of CNMs. In resent ten years, the method of high-temperature electrochemical synthesis (HTES) in molten salts has been rapidly developing. The essence of the method of HTES is the cathodic reduction of oxygen-containing carbon compounds dissolved in molten salts. There are several variants of HTES. The advantages of all variants of HTES are: (1) soft synthesis conditions, (2) simple hardware implementation, (3) the possibility of controlling the electrolysis conditions, (4) low energy consumption for electrolysis, (5) the use of cheap precursors, (6) easy doping during synthesis, (7) monodipersity of the product. An important advantage of HTES is the possibility of using carbon dioxide as a starting reagent. Global warming, caused by increase in the emission of greenhouse gases (CO2, CH4 and others), is recognized as a serious environmental problem of the mankind.The goal of this work is presentation of research results on the electrochemical transformation of carbon oxy-compounds (lithium carbonate and carbon dioxide) into nanoscale solid carbon of different structure and morphology (carbon nanotubes (CNTs), fibers (CNFs), graphene) in chloride-carbonate melts.On the basis of a voltammetric study, it has been found that direct electroreduction of CO2 dissolved in equimolar salt mixture Na,K|Cl under an excessive pressure (1 - 15 atmospheres) up to carbon at temperature 750 0C occurs in one stage at polarization rates above 0.2 Vs-1. The electrode process is controlled both by the charge transfer rate and by the rate of gas diffusion to the electrode. At polarization rates below 0.1 Vs-1, the electrode process occurs in two stages, and an Electrochemical-Chemical- Electrochemical mechanism of CO2 reduction has been suggested. The cathodic product is carbon films and powders of different structures and morphology. Typical morphologies of the electrolytic products obtained in the melts Na,K|Cl–CO2 are shown in Fig. 1.All the products obtained in the system Na,K|Cl–CO2 (10 atm.) contain CNTs, the majority of which are multi-walled and have a curved form (structural defects). Most often CNTs agglomerate into bundles, and more rarely are arranged as individual tubes. The outer diameter of CNTs varies from 5 to 250 nm, while the internal diameter from 2 to 140 nm. Almost all CNTs are filled partly with electrolyte salt. When the current density increases, the CNT diameter decreases (although every product obtained at the current densities used has CNTs of different diameters).It was found by voltammetry method that the process of reduction of Li2CO3 in Na,K|Cl melt depends on the gaseous atmosphere above the melt. In air, it includes two electrochemical stages. The preliminary chemical reaction of lithium carbonate dissociation (Li2CO3 ⇄ Li2O + CO2) leads to the formation of two electrochemically active particles: CO2 and LixCO3 2-x, which are reduced to elemental carbon at different potentials of -0.8 and -1.7 V respectively against Pt|O2/O2- reference electrode. Both processes are irreversible, and the electroreduction of LixCO3 2-x takes place with diffusion control of the delivery of the depolarizer to the electrode surface. Under of argon or carbon dioxide atmosphere over the melt, the process of lithium carbonate dissociation is suppressed; therefore, the deposition of carbon in this case occurs only from the cationized carbonate complex.X-ray diffraction, SEM and Raman spectroscopy revealed that the cathode product is a high disordered amorphous carbon. Agglomerated particles consist of degraded graphite structures with an approximate crystallite size of 30–40 nm.Figure 1. TEM micrographs (a÷e) and electron-beam images (d (inset in the upper left) and f) of carbon powders produced in the system Na,K|Cl–CO2 (10 atm.) at different current densities: (a ÷ e): i k = 13.5; 28; 42; 56; 72 mA/cm2 ; T = 750 0C; Figure 1

Electrochemical Synthesis of Selenium‐substituted Benzoxazine via Radical Initiated Cyclization

AbstractA strategy for electrochemically synthesizing selenium benzoxazines through o‐vinylaniline and diselenide has been developed. This metal‐free and oxidant‐free electrochemical synthesis method is carried out in an undivided cell under mild conditions, which is more environmentally friendly. Moreover, a variety of selenium‐substituted benzoxazine can be prepared in good yield with a broad scope and functional group tolerance, which has potential industrial application value.

Removal of cesium from liquid radioactive waste by in situ electrochemical synthesis of cesium zinc ferrocyanide

Cesium ion in the simulated liquid radioactive waste was treated with cesium zinc ferrocyanide (CsZnFC) precipitate synthesized by in situ electrochemical synthesis method (ISESM) in this study. The best removal rate of Cs+ was 99.42%, and the residual Cs+ in the effluent was 29.13 μg L‐1 under the optimal experimental conditions of initial pH (pHint) of 7.0, reaction temperature (T) of 35 °C, current density (J) of 0.7 mA cm−2, electrolytic time (t) of 30 min, and molar ratio of [Fe(CN)6]4- to Cs (RFCN/Cs) of 1.0. The synthesized precipitate was characterized by SEM-EDS, XRD and FT-IR. The precipitated particles are cubic with a particle size of around 190 nm. The XRD pattern shows that the phase composition of the synthesized compound is Cs2Zn[Fe(CN)6], and the absorption peaks of O–H bonds, C–N bonds, and C–Fe bonds appear in IR spectrum. The method of in situ electrochemical synthesis of CsZnFC is promising for the treatment of liquid radioactive wastes.

Construction of polypyrrole nanowires@cobalt phosphide nanoflakes core–shell heterogeneous nanostructures as high-performance electrodes for supercapacitors

• PPy@CoP CSHNs are synthesized using a two-step electrodeposition method. • PPy nanowires are wrapped by intercrossing CoP nanoflakes. • The PPy@CoP electrodes demonstrate enhanced rate capacities and cyclic stability. • Unique structural advantages account for the improved energy storage performance. In this reported work, polypyrrole (PPy)@cobalt phosphide (CoP) core–shell heterogeneous nanostructures (CSHNs) are grown directly on the Ni foam using a two-step electrochemical synthesis method. The morphology and microstructure analysis reveal that PPy nanowires are uniformly wrapped by intercrossing CoP nanoflakes, which endows the CSHNs with abundant electroactive sites, high electrical conductivity, and good structural stability. Electrochemical studies show that the PPy@CoP CSHNs as supercapacitor (SC) electrodes demonstrate a higher specific capacity (443C g −1 at 1 A g −1 ) and better cycling performance (93% initial capacity retention after 5000 cycles at 5 A g −1 ) than the pure PPy and CoP electrodes. Besides, a hybrid supercapcitor (HSC) device with the PPy@CoP positive electrode yields a high energy density of 38.1 Wh kg −1 at a power density of 750 W kg −1 . This work offer a new insight into the rational design of the heterostructures based on PPy and metal phosphides for application in high-performance SCs.

Enhanced struvite generation and separation by magnesium anode electrolysis coupled with cathode electrodeposition

Adding magnesium ions (Mg2+) to produce struvite is an important method to recover nitrogen and phosphorus from wastewater. Both the Mg2+ source and subsequent separation of struvite are key factors for the utilization of struvite. In this study, we developed an efficient method to recover nutrient salts from wastewater using sacrificial Mg anodes to generate struvite, with its simultaneous separation through cathode electrodeposition. The anode-released Mg2+ reacted with NH4+-N and PO43−-P in bulk solution to form struvite, which was more intense on the cathode surface due to the relatively higher pH environment from hydrogen evolution, resulting in most of the struvite being deposited on the cathode surface and simultaneously separated out of the bulk solution. Using a cathode with a higher solution-cathode interface area and relatively low current density facilitated struvite deposition. Results showed that under optimal electrolysis condition (5.76 A/m2, pH 8.5, 180 min, and 1.2:1.0 Mg:P), 91% of the undissolved substances as the phosphate precipitation were deposited on the graphite cathode surface, and the proportion of struvite in the deposition reached 41.52%. This study provides a novel electrochemical method for struvite synthesis and separation for the recovery of nitrogen and phosphorus from wastewater.

Synthesis of Oligosaccharides of Glucosamine by Automated Electrochemical Assembly

The automated electrochemical assembly is one of our arrial points for development of electrochemical methods for oligosaccharide synthesis. The one-pot sequential process of activation of thioglycoside building block by electrochemical oxidation and coupling with thioglycoside building block can be carried out in automated manner, and muliple cycles of the process enables us to synthesis oligosaccharides with desired chain length. We have synthesized oligoglucosamines with β-1,6- and β-1,4-glycosidic linkages. Total synthesis of TMG-chitotriomycin and Myc-IV (C16 : 0, S), which are biologically active oligoglucosamines derivatives, has also achieved. Ionic liquid tags were introduced to glucosamine building blocks to facilitate separation of products; however, they worked not only separation tag but also electrolyte and stereo-controlling group in electrochemical glycosylation. We also found that electrochemical glycosylation was also useful to convert linear oligosaccharides of glucosamines into the corresponding cyclic oligosaccharides.

Wafer-scale quasi-layered tungstate-doped polypyrrole film with high volumetric capacitance

Layered materials are particularly attractive for supercapacitors because of their unique physical, electrical and chemical properties. Here, we demonstrate a facile and scalable electrochemical deposition method for wafer-scale synthesis of quasi-layered tungstate-doped polypyrrole films (named TALPy) with controllable thickness and size. The as-prepared TALPy film exhibits a high gravimetric density and excellent volumetric capacitance, exceeding many high-performing carbon- and polymer-based film electrodes. Based on combined results of ex-situ X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS), it is determined that TALPy stores charge through an ion intercalation process accompanied by change in oxidation states of polypyrrole backbone, which is referred as intercalation pseudocapacitance. All these results suggest the great promise of electrochemical deposition as a scalable and controllable bottom-up approach for synthesizing quasi-layered conductive organic-inorganic hybrid films for electrochemical energy storage applications with high volumetric performance.

State of art of valorising of diverse potential feedstocks for the production of alcohols and ethers: Current changes and perspectives

Alcohols could be the biggest factor for the improvement of world biofuel economy in the present century due to their excellent properties compared to petroleum products. The primary concerns of sustainable alcohol production for meeting the growing energy demand owing to the selection of viable feedstock and this might enhance the opportunities for developing numerous advanced techniques. In this review, the valorization of alcohol production from several production routes has been exposed by covering the traditional routes to the present state of the art technologies. Even though the fossil fuel conversion could be dominant method for methanol production, many recent innovations like photo electrochemical synthesis and electrolysis methods might play vital role in production of renewable methanol in future. There have been several production routes for production of ethanol and among which the fermentation of lignocellulose biomass would be the ultimate choice for large scale shoot up. The greenhouse gas recovery in the form of alcohols through electrochemistry technique and hydrogenation method are the important methods for commercialization of alcohols in future. It is also observed that algae based renewable bio-alcohols is highly influenced by carbohydrate content and sustainable approaches in algae conversion to bio-alcohols would bring greater demand in future market. There is a lack of innovation in higher alcohols production in single process and this could be bounded by combining dehydrogenation and decarboxylation techniques. Finally, this review enlists the opportunities and challenges of existing alcohols production and recommended the possible routes for making significant enhancement in production.

Electrochemical Oxidation of 2,3-Dihydroxypyridine in the Presence of Benzenesulfinic Acid: A Green Method for the Synthesis of a Novel Heterocycle Dye

A green method for the one-pot electrochemical synthesis of a novel highly oxygenated heterocycle dye, 3,8-dihydroxy-4,9-bis(phenylsulfonyl)dipyrano[2,3-b:2′,3′-e]pyrazine-2,7-dione (PSO), is reported. The synthesis of this compound was performed by anodic oxidation of 2,3-dihydroxypyridine (DHP) in the presence of benzenesulfinic acid (BSA) in aqueous acetate buffer solution, using a carbon electrode. The cyclic voltammogram of DHP shows an irreversible anodic peak corresponding to two-electron oxidation of DHP to pyridine-2,3-dione (PDO), while, the CV of the mixture of DHP and BSA exhibits a new anodic peak at more positive potentials which is a confirmation of the reaction between electrogenerated PDO and BSA. Based on the electrochemical evidence, a novel mechanism for the synthesis of PSO is proposed. The synthesis of PSO was conducted in aqueous acetate buffer (pH = 4.0, c = 0.2 M), by controlled potential method (at 0.90 V vs Ag/AgCl electrode, yield 69%) as well as by constant current method (at J = 1.12 mA cm−2, yield 63%) in a divided cell, under green conditions. Furthermore, the pH dependent anodic behavior of 2,3-dihydroxypyridine was investigated. Our data shows that the E pA–pH diagram indicates the presence of five predominant regions. The predominant species across all regions were identified.

Electrochemical methods for synthesis and in situ generation of organometallic compounds

• Electrochemical methods have been used for the preparation of organometallic compounds. • Main electrochemical synthetic and analytical methods and types of the electrochemical cells are described. • The electrochemically generated high-reactive organometallic species have been used in situ as the reagents for the synthesis of organic and organoelement compounds. • The application of in situ spectroelectrochemical methods for elucidating of the nature of organometallic intermediates formed in the electrochemical process and their application for the activation of organometallics for catalytical purposes are discussed. The electrochemical methods have a huge synthetic potential in both academia and industry. However, the implementation of electrochemistry for the synthesis of organometallic compounds is presented limitedly, while the sustainability and greenness of the electrochemical protocols allow considering them as a very promising and intriguing approach. This review summarizes the most important and practically useful advances in the electrochemistry of organometallics with the emphases on the direct electrochemical synthesis of organometallic derivatives by the formation of a carbon–metal bond, electrosynthesis of organic compounds mediated by in situ generated organometallics as well as cyclic voltammetry and related techniques, applied for analysis and preparation of organometallic compounds.

Synthesis of carbon quantum dots from apple juice and graphite: investigation of fluorescence and structural properties and use as an electrochemical sensor for measuring Letrozole

In this study, hydrothermal method was used to prepare carbon quantum dots from the natural apple juice and electrochemical synthesis method was used to prepare carbon quantum dots from graphite. The effect of synthesis type and current intensity on fluorescence and structural properties of the prepared carbon quantum dots was investigated. TEM and FTIR techniques were used for chemical and morphological study of carbon quantum dots. The synthesized carbon quantum dots were used for modification of the surface of the glassy carbon electrode and were used as an electrochemical sensor to measure Letrozole. According to the results, the sizes of apple juice-based carbon quantum dots were 5–10 nm and the sizes of graphite-based carbon quantum dots were 1–5 nm. With the increase and the intensity of the applied current in the electrochemical synthesis method, the particle size became larger and their fluorescence intensity decreased. The FTIR results confirmed the synthesis of the carbon quantum dots and the corresponding functional groups. Modified electrodes with a variety of carbon quantum dots showed a good response to Letrozole. The prepared sensor showed a good selectivity for Letrozole compared to similar drug (Clomifene). The sensitivity of the optimal sensor to Letrozole was 0.111 (A/M) while to Clomifene drug was 0.041 (A/M). The sensor was able to measure Letrozole in the concentration range of 1–12 × 5−5 M and the detection limit was 1.85 × 5−5 M. The results showed that the designed sensor with the appropriate recovery percentage can measure Letrozole in real drug samples.

Co-Solvent Free Electrochemical Synthesis of Biodiesel Using Graphite Electrode and Waste Concrete Heterogeneous Catalyst: Optimization of Biodiesel Yield

This study optimized a co-solvent free electrochemical method for biodiesel synthesis using graphite electrode and waste concrete heterogeneous catalyst. Various parameters were evaluated, including: applied voltage (9.6, 14.4, 19.2 V), catalyst particle size uniformity (unfiltered and filtered with 150 mesh), and reaction time (15, 30, 120, 240 min). The results obtained 100% FAME content and 78.51% of biodiesel yield that were achieved at 14.4 V within 30 min using filtered catalyst and cooking oil feedstock. However, a slight decline was observed with the use of waste cooking oil. This optimized method offers a reliable and simple condition for mass biodiesel production. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).