Electrochemical Method For Synthesis Research Articles

An efficient electrochemical method for the atom economical synthesis of some benzoxazole derivatives

Electrochemical synthesis of some 2-arylbenzoxazoles were directly carried out via the electrochemical oxidation of 3,5-di-tert-butylcatechol in the presence of benzylamines without using any catalyst under mild and green conditions. The results show that electrogenerated 3,5-di-tert-butyl-1,2-benzoquinone participates in the reaction with benzylamine derivatives and, via the ECCE mechanism “electron transfer + chemical reaction (imine formation) + chemical reaction (cyclization) + electron transfer”, converts to the corresponding benzoxazole derivatives. In this work, some benzoxazole derivatives with high yields in aqueous solutions, without toxic reagents and solvents at a carbon electrode using an environmentally friendly novel method, are provided.

Electrodeposition of a novel CdTe array on Ni foils and photoelectrochemical performance

A novel perpendicularly aligned CdTe array with cauliflower-like morphology was fabricated on a Ni substrate using a simple electrochemical synthesis method. The samples were characterized by XRD, EDX and FESEM, and the results demonstrate that a high-purity, uniform cauliflower-like CdTe array was obtained. Rod lengths can reach to 3.0 μm, with nanoparticles stacking along the rod growth direction, keeping the diameter at 1.5 μm. A schematic diagram of the possible growth process and evolution from CdTe seed nuclei to the cauliflower-like CdTe array was proposed. The device based on the aligned array-on-Ni configuration demonstrates excellent photoelectrical properties, which is ascribed to the large absorption coefficient of the material and also suggests good electronic structure quality of the cauliflower-like rods. The technique described is applicable to fabricate highly aligned cauliflower-like semiconductor arrays on other conductive substrates.

Electrochemical synthesis of gold nanoparticles on the surface of multi-walled carbon nanotubes with glassy carbon electrode and their application

Gold nanoparticles on the surface of multi-walled carbon nanotubes with glassy carbon electrode were prepared using electrochemical synthesis method. The thin films of gold Nanoparticles/multi-walled carbon nanotubes were characterized by scanning electron microscopy, powder X-ray diffraction, and cyclic voltammetry. Electrochemical behavior of adrenaline hydrochloride at gold nanoparticles/multi-walled carbon nanotube modified glassy carbon electrode was investigated. A simple, sensitive, and inexpensive method for determination of adrenaline hydrochloride was proposed.

Polymer to Electrode Adhesion Enhancement Based on Novel PI/Au (Nanolayer)/Polypyrrole Three-Bending-Beam Actuator Fabrication

Novel combined electrochemical and chemical synthesis methods for the preparation of Polypyrrole-based actuators are presented. Polypyrrole (PPy) actuators were electrochemically synthesized and after coating with a thin gold nano-layer, prepared into a Polyethersulfone (PI) substrate. Scanning Tunneling Microscopy (STM) and a potentiostat–galvanostat were used to confirm the actuation of PPy based actuators during the redox process. Three-layer actuator based on polypyrrole as electroactive material, Polyethersulfone as substrate and gold nanolayer in our proposed method have been realized. The structure strength and layer adhesion have been improved. This advancement in conducting polymer actuator technology will impact many engineering fields, where a stable, lightweight and large displacement actuator is needed.

Effect of swift heavy ion beam irradiation on Au–polyaniline composite films

In this paper, two-step electrochemical synthesis method is reported for the fabrication of Au–polyaniline (Au–PANI) composite film. Initially, PANI film was electrochemically synthesized by using chronopotentiometery with optimized process parameters on platinum electrode. The synthesized PANI film acts as working electrode for the decoration of Au particles on the surface of PANI film by using cyclovoltammetry (CV) technique. Later, these films were irradiated under high vacuum (∼5×10−6Torr) at room temperature with 40MeV C5+ ion beam at various fluences ranging from 1×1011 to 1×1013ions/cm2. The Au–PANI composite films were characterized before and after irradiation by using micro-Raman, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The characteristic peaks of the Raman spectrum of Au–PANI composite films were reduced after irradiation. XRD spectra exhibited the decrease in the peak intensity. Moreover, interchain distance, interplanar distance, micro strain, dislocation density and distortion parameters were calculated. The analysis revealed a significant variation in these parameters with an increase in the ion fluence, which is in line with the Raman analysis. SEM shows the formation of clusters with porous structure after irradiation.

A new method for fabrication of graphene/polyaniline nanocomplex modified microbial fuel cell anodes

A novel microbial fuel cell (MFC) anode is fabricated by electrochemically reducing graphene oxide (ERGNO) first and coating polyaniline (PANI) nano-fibers afterward on the surface of carbon cloth (CC). ERGNO/CC is prepared using an electrochemical synthesis method reducing graphene oxide by cyclic voltammetry (CV) in phosphate buffer solution (PBS, pH = 6.9). Combining the advantages of PANI and ERGNO, PANI–ERGNO/CC yields a maximum power density of 1390 mW m−2 when used as the MFC anode, which is 3 times larger than that of the MFC with the CC anode. The electrodes are characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The electrochemical activities have been investigated by CV and electrochemical impedance spectroscopy (EIS). The great improvement is attributed to the fact that graphene not only serves as a highly conductive support material, but also provides large surface for PANI. High conductivity and large specific surface area greatly improve the charge transfer efficiency and the bacterial biofilm loading. In this work, a practical and promising synthesis method is developed to fabricate high-performance MFC anodes.

Study of Electrochemical Oxidation of Catechol Derivatives in the Presence of 1-Phenyl-3-Methyl-5-Pyrazolone as a Nucleophile

Recently, 1-phenyl-3-methyl-5-pyrazolone (PMP) 9 and its methoxy analog, 1-(p-methoxy)-phenyl-3-methyl-5-pyrazolone (PMPMP) 10 have been used for pre-column derivatization of carbohydrates. The nucleophilic activity of these compounds is well known. 11,12 The electrochemical synthesis of organic compounds is a wellestablished technique and has been widely implemented for syntheses ofmaterialsthatarenotaccessiblebyconventionalmethods. 5 Electrochemical methods for the synthesis of organic compounds are green methods that utilize environmentally friendly solvents, a great advantage of these methods. 13 In addition, it is possible to monitor the synthesis process by electrochemical methods. 14 In the present work electrochemical activity of catechol compounds was studied in the presence of 1-phenyl-3-methyl-5pyrazolone as a nucleophile and the reaction mechanism was monitored by means of cyclic voltammetry and controlled-potential coulometry. The products were synthesized by an electrochemical method and characterized by means of FT-IR, 1 HNMR, 13 CNMR, MS spectroscopy and elemental analysis. The products were obtained in good yields and high purity. Theses materials might be used as analgesics in medical applications. 15

Electrochemical Synthesis of Iron-Based Superconductor FeSe Films

Superconducting FeSe films were successfully fabricated using electrochemical synthesis methods. The composition ratio of Fe and Se was controlled by electric potential and pH value. We found that the FeSe film deposited at an electric potential of -1.75 V vs Ag/AgCl at a pH value of 2.3 exhibits a superconducting transition at 3.5 K. The electrochemical synthesis technique that we have developed will offer many advantages for applications.

Fabrication of CdS nanotubes assisted by the template-free electrochemical synthesis method and their photo-electrochemical application

A cadmium sulfide nanotube (CdS NT) was successfully fabricated by a two-step route consisting of the template-free electrochemical deposition of cadmium hydroxide films at 298K and their subsequent sulfurization by S2− ions. Photo-electrochemical solar cells using a combination of CdS NT, polysulfide (Sx2−/xS2−) and carbon electrode exhibited high IPCE (ca. 80%) at 510nm due to efficient light-harvesting performance.

Combined chemical and electrochemical synthesis methods for metal-free polypyrrole actuators

Novel combined chemical–electrochemical synthesis routes for the preparation of metal-free air-operated polypyrrole-based actuators are presented. The chemical synthesis phase provides the conductive electrode surface for the well-controllable electrochemical deposition of the working PPy material. Several new techniques not previously used in conducting polymer actuator preparation are described, including vapor-polymerization, oxidizer-painting and low temperature electrosynthesis in mixed aqueous solutions. Both commercially available and in-house membranes were used. The three described methods yielded well reproducible, functional actuators with acceptable displacement, strains and strain-rates. The most important characteristics of the actuators are presented.

The decision of ecological problems during utilization of components of galvanic productions sewages

The article deals with physical and chemical regularities of chemical and electrochemical ionization of copper and its alloys. The aim of research is studying of physical and chemical properties of copper and zinc-containing systems, intensification of copper and its alloys ionization and the development of efficient resource-saving ways of exhausted electroplating electrolytes regeneration. The parameters of chemical and electrochemical copper dissolution in chloride electrolytes are determined; the changing of limiting step nature during copper electrochemical dissolution is established; the modification of passive layer on the copper surface is shown; the efficiency of copper and zinc separation in sulphate systems using contact displacement of copper by zinc. The experimental data is used as the basis for low-waste resource-saving technological processes development: regeneration of exhausted etching CuCl 2 and FeCl 3 solutions; the electrochemical method of fungicide copper hydroxochloride synthesis; brass etching solution regeneration during contact displacement of copper by zinc and crystallization deposition of metal compounds. The results of research can serve as the basis for development of new compositions of copper and its alloys effective high rate chemical etching; intensification of metal etching processes and the development of spent technological electrolytes regeneration methods

Microwave Assisted Synthesis of ZnO Nano-Sheets and Their Application in UV-Detector

Here we report a low cost electrochemical aqueous solution method for synthesis of high quality two dimensional flat ZnO nano-sheets using standard home use microwave-oven. Independent studies by field emission scanning electron microscopy and high resolution transmission electron microscopy confirm the formation of very thin graphene-like nanosheets of ZnO. The high quality of the sheets is confirmed from a photoluminescence study, which shows the presence of a narrow and sharp band edge emission at 360 nm and the presence of a weak defect related emission peak in the visible region. The conductivity of the nanosheets increases dramatically upon illumination of UV lights as compared to the dark condition. The better crystal quality and excellent photo conductivity ensure these ZnO nanosheets can be used as potential UV detector. It is also found that both response and recovery times of ZnO nano-sheets are very fast and are comparable to those of nanowires and nanorods.

Electrochemical synthesis of wheat-like CdSe array and their photoelectrochemical properties

It is reported here that a wheat-like CdSe array on an ITO substrate has been developed by a simple electrochemical synthesis method. These samples were characterized by XRD, EDX and FESEM, whose results demonstrate that a high-purity, uniform hexagonal wheat-like CdSe array was obtained. Photoelectrochemical solar cells are constructed using the wheat-like CdSe array as the photoanode in a polysulphide electrolyte and their power output characteristics are studied. The photoelectric conversion efficiency of the photoelectrochemical solar cells based on the wheat-like CdSe array on an ITO substrate, which are prepared in electrolyte solution containing CdSO4 (0.01 M) + Na2SeO3 (0.01 M) + H2SO4 (0.208 M), can reach a value of 1.15%.

Voltammetric sensors with chiral recognition capability: The use of a chiral inducing agent in polyaniline electrochemical synthesis for the specific recognition of the enantiomers of the pesticide dinoseb

An electrochemical method for chiral polyaniline synthesis has been optimised to develop voltammetric sensors capable of target enantiomer recognition. The methodologies for both R- and S-specific sensor development have been carefully optimised in order to obtain the highest chiral discrimination capacity. R and S specific sensors were synthesised potentiostatically at 0.5 V and 0.6 V, respectively in 0.28 M R- or S-camphorsulphonic acid, which acted as a chiral inducing agent. Higher potential values led to polymer degradation. The proposed methodology allows the generation of sensors which are able to bind the different enantiomers of the pesticide dinoseb with good sensitivity and repeatability (RSD < 10%). Thereby the resulting R- and S- sensors showed a very high capability to bind selectively the target enantiomer from a racemic mixture. The proposed method could be also extended easily to selective recognition of enantiomers of other chiral compounds.

Investigation on synthesis and size control of copper nanoparticle via electrochemical and chemical reduction method

Copper nanoparticles were synthesized and the effect of the operating conditions via both chemical and electrochemical synthesis methods was investigated in this paper. In the chemical reduction method, copper nanoparticles were prepared in a copper sulfate solution using NaBH4 as reducing agent and then stabilized in the presence of polyvinylpyrrolidone under nitrogen atmosphere. Temperature and concentration ratio of reducing agent to precursor influenced the synthetic progress and size of the copper nanoparticles. Copper nanoparticles with average particle size 30 nm were formed when the concentration ratio is greater than 2 in the temperatures range from 60 to 75°C. In the electrochemical deposition method, copper nanoparticles were prepared using a bath containing homogeneously acidified copper sulfate solution. The nanoparticles were formed as spongy layers on the plating electrode which is easily separated. Average particle size 10 nm of copper nanoparticles is obtained with controlling of the electrolyte concentration and current density. The comparison shows that electrochemical deposition gives finer particle of copper but size controlling of the nanoparticles are more controllable than the chemical reduction method. Key words: Copper nanoparticles, operating conditions, electrochemical deposition, chemical reduction.

Synthesis and photoelectric characterization of semiconductor CdSe microrod array by a simple electrochemical synthesis method

It is reported here that the microrod array of CdSe on indium doped tin oxide coated conducting glass (ITO) substrate has been developed by a simple electrochemical synthesis method. The electrodeposition of CdSe was also investigated by cyclic voltammetric technique. The sample was characterized by XRD, EDX, FESEM and UV–vis spectroscopic. The X-ray diffraction investigation demonstrates that the CdSe microrod is a uniform hexagonal CdSe crystal. EDX shows that the high purity CdSe is obtained. Field emission scanning electron microscope (FESEM) results show that the microrods’ length, diameter, and direction of growth are nearly uniform and perpendicular to the ITO substrate. UV–vis absorption spectrum study shows the presence of direct transition with the band gap energy 2.13 eV. Photoelectrochemical solar cells are constructed using CdSe microrod array as the photocathode in polysulphide electrolyte and their power output characteristics are studied.

Growth of Different Shape Cu&lt;SUB&gt;2&lt;/SUB&gt;O Micro Structures Using PEDOT Coated ITO Electrode

Crystalline cuprous oxide (Cu2O) particles were successfully deposited on poly(3,4-ethylenedioxythiophene) [PEDOT] coated indium tin oxide (ITO) glass. PEDOT film was first prepared on ITO glass by electrochemical polymerization. Crystalline Cu2O particles were then deposited on the PEDOT film by applying various electrochemical synthesis methods using a copper sulfate precursor. The effects of applied electrochemical methods on the compositions, grain sizes and shapes, and surface morphologies of the electrodeposited films were investigated. The micro structures of Cu2O particles were confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). When the cyclic voltammetry (CV) and chronoamperometry (CA) were applied, fine Cu2O particles of cubic and pyramidal phase were formed, respectively. However, bare ITO electrode was used, metallic copper particle was obtained. It shall be assumed that PEDOT might act as a buffer layer in electrochemical reduction of cuprous ion. The details of PEDOT behavior will be the topic of future studies.

Synthesis of electrochemically-reduced graphene oxide film with controllable size and thickness and its use in supercapacitor

An electrochemical synthesis method of reducing graphene oxide (GO) under constant potential is reported. Electrochemical technique offers control over reaction parameters such as the applied voltage, electrical current and reduction time; whereas the desired size and thickness of the film can be pre-determined by controlling the amount of precursor GO deposited on the electrode with defined shape and surface area. This synthesis technique produces high quality electrochemically reduced GO (ERGO) film with controllable size and thickness. Electrochemical symmetrical supercapacitors based on ERGO films achieved a specific capacitance of 128 F/g with an energy density of 17.8 Wh/kg operating within a potential window of 1.0 V in 1.0 M NaNO 3. The supercapacitor was shown to be stable, retaining ca. 86% of the original specific capacitance after 3500 charge–discharge cycles. The results indicate that this simple synthesis technique for providing graphene-like materials has great potential in various applications such as energy storage.

Electrochemical synthesis of the new substituted phenylpiperazines

Abstract Electrochemical oxidation of 1-(4-(4-hydroxyphenyl)piperazin-1-yl)ethanone ( 1 ) has been studied in the presence of arylsulfinic acids ( 3a–c ) as nucleophiles in aqueous solutions using cyclic voltammetry and controlled-potential coulometry methods. The results revealed that quinone-imine derived from oxidation of 1 participates in Michael type addition reaction with 3a–c and via an EC mechanism converts to the corresponding new phenylpiperazine derivatives. The present work has led to the development of a facile and environmentally friendly reagent-less electrochemical method for synthesis of some new phenylpiperazine derivatives in aqueous solutions with high atom economy and safe waste under ambient conditions and in an undivided cell using a carbon electrode.

A new highly sterically demanding silyl (TEDAMS) group. Synthesis by multiple substitution of tris(diphenylmethyl)silane with diarylcarbenium ions

A highly efficient electrochemical method for synthesis of halosilanes bearing bulky substituents was developed. Electrophilic multiple substitution on tris(diphenylmethyl)silane with diarylcarbenium ions afforded a highly sterically demanding hydrosilane, tris(extended diarylmethyl)silane (TEDAMS-H), which was converted to the corresponding bromosilane (TEDAMS-Br).