Papers by Keyword: Chronoamperometry

Abstract: This study explores the utility of reduced graphene oxide (rGO) as a support material for gold nanoparticles (AuNPs) synthesized via an economically efficient and environmentally friendly electrochemical deposition method conducted at room temperature. Employing a chronoamperometry (CA) method, we successfully synthesize AuNPs in aqueous solutions without additional stabilizing agents. We investigate the influence of substrate and electrodeposition duration on the growth of AuNPs, on indium tin oxide glass substrates and rGO, with electrodeposition durations for comparison. This research highlights the straightforward and rapid one-step synthesis of AuNPs in an aqueous medium and explores the correlation between Au particle size and electrocatalytic performance. We evaluate the electrochemical performance of rGO-supported AuNPs in the context of methanol oxidation reaction (MOR) using cyclic voltammetry in an aqueous medium with an alkaline electrolyte. Notably, AuNPs supported by rGO, featuring an average particle size of 46 nm, exhibit superior electrochemical performance compared to their counterparts with an average particle size of 165 nm when employed as catalysts for the MOR. This superior performance is characterized by a 15 mV more negative oxidation potential (54 mv compared to 39 mV) and over 2.5 times higher oxidation peak current (0.064 mA compared to 0.025 mA), underscoring their efficiency as electrocatalysts for MOR.

Abstract: The effect of trisodium citrate on the electrodeposition of nickel-copper-molybdenum in sulfate solution was explored in this paper. According to the results of the nickel-copper-molybdenum electrodeposition experiment, adding a certain amount of trisodium citrate into the electrodeposition solution inhibited the hydrogen precipitation reaction and accelerated the crystallization process on the plated surface to a certain extent, thereby improving the cathodic current efficiency. However, no change occurred to the nucleation mode in the process of electrodeposition crystallization, and it was consistent with the theoretical value of instantaneous nucleation before the peak current (t/t_m≤ 1) was reached. The theoretical values of instantaneous nucleation were consistent. The epitaxial growth rate constant K^* of the crystals was reduced after the addition of trisodium citrate into the electrodeposition solution, indicating the inhibitory effect of trisodium citrate on the growth of crystals in the electrodeposition solution. The diffusion coefficient of the nickel-copper-molybdenum ligand ions was reduced as well, suggesting the inhibitory effect of adding trisodium citrate into the plating solution on the cathodic mass-transfer process, which is conducive to promoting its cathodic polarization. Meanwhile, the growth rate of crystals was significantly affected by the applied potential.

Abstract: Elecrodeposited Ni-P alloy thin films have been the subject of extended investigations, since the pioneering works of Brenner et al, in the late 1940s. It is well known, that the physical and chemical properties of the Ni-P deposit composition are strongly influenced by the preparation conditions. In our experimental procedure, we have used a Parstat 2253 potensiostat equipped with Power-Suite software. All the electrochemical experiments were performed in a three electrode cell in which the volume of the bath was 150ml, in this experimental technique, we can measure one or more of three parameters: the potential (V), current (i), and time (t). The aim of our work consists to study the nucleation and growth process and given morphology and composition of electrodeposited Ni_x-P_100-x thin films on Copper substrates. For this purpose, cyclic voltametry and chnonoamperomaty have been used in order to determine the previous cited properties of thin films Ni-P, [0.10 of NaPH₂O₂ solutions. The chrnoamperogramms can be interpreted by the use of one of three models called: Growth mode (Me layer by layer formation); Franck Van der Merwe, FM model, Growth mode 3D (Me island formation on the top of predeposited), 2D Meads overlayers on substrat and Stranski-Krastanov; (SK model).

Abstract: Aniline was polymerized with mmt (Montmorrillonite) by chemical oxidation method using potassium perdisulphate. The solubility of the chemically prepared polymer–clay nanocomposite was ascertained and it showed good solubility in DMSO and DMF. The Pani–mmt nanocomposites were characterized by UV–Vis, FTIR spectral studies. Amine vibration peak observed at 1593 cm-1 was shifted to lower wave numbers when the polymer–clay nanocomposites were formed. The X-ray diffraction studies revealed the formation of nano sized (26 nm) crystalline nanocomposite. SEM analysis showed mixed granular nature of the polymer–clay nanocomposite in which polymer was intercalated with the clay. EDAX analysis shows the presence of Na, Mg Al, Si, C and N. Cyclic Voltammetric studies exhibit good adherent behaviour on electrode surface at pH 1.0. It exhibited two oxidation peaks at 0.360V and 0.638V and two reduction peaks at 0.431V & 0.103V. Chronoamperometric and chronocoulometric studies were also carried out at inert as well as oxidation atmosphere.

Abstract: Aniline was polymerized with TiO2 by chemical oxidation method using Potassium perdisulphate. The solubility of the chemically prepared polymer–ceramic nanocomposite was ascertained and it showed good solubility in DMSO and DMF. The Pani–TiO2 nanocomposite was characterized by UV–Vis, FTIR spectral studies. Amine vibration observed at 1593 cm-1 was shifted to lower wave numbers when the polymer–ceramic nanocomposites were formed. The X-ray diffraction studies revealed the formation of nano sized (26 nm) crystalline polymer. SEM analysis showed mixed granular nature of the polymer–ceramic nanocomposite. EDAX analysis shows the presence of Ti, C and N. Cyclic Voltammetric studies exhibit good adherent behaviour on electrode surface at pH 1.0. It showed the presence of oxidation peaks at 0.271V and 0.623V and reduction peaks at 0.832 and 0.493V. CV, Chronoamperometric and chronocoulometric studies were also carried out at inert as well as oxidation atmosphere.

Abstract: Electrodeposition was carried out on mild steel surface in 0.3 M sodium hydroxide solution (70% distilled water: 30% ethanol) containing 0.1 M salicylideneaniline using cyclic voltammetry and chronoamperometry techniques. Both techniques show the formation of the films on the mild steel surface. The corrosion behavior of electrodeposited mild steel was studied using electrochemical impedance spectroscopy (EIS) technique at various immersion times in 0.5 M sodium chloride solution (NaCl). The study indicates that the resistance of mild steel against corrosion increases after being electrodeposited with salicylideneaniline. However the films tend to diminished after 24 hours being immersed in 0.5 M NaCl solution.

Abstract: An Ag nanoparticle included Glassy carbon (GC)/poly [3, 4-ethylenedioxythiophene] (PEDOT) modified electrode was organized by a straightforward electrochemical method without using any stabilizer or reducing agent. The obtained working electrodes showed a high conductivity when compared to the bare electrode. It also shows superior ability of electrochemically sensing towards the electroreduction of H2O2 with no need for an enzyme or mediator immobilized in the electrode. Under optimum condition the detection limit using chronoamperometry response was estimated to be 0.61 M based on the criterion of signal-to-noise ratio of 3 (S/N of 3).

Abstract: Electrochemical real-time PCR (EC-rtPCR) overcomes several shortcomings of fluorescence-based real-time PCR. But traditional electrochemical method has some limitations which reduce the accuracy and efficiency of testing. To overcome the disadvantages of chronoamperometry (CA) we report a novel electrochemical method where a peak current is quickly generated for the current vs. time curve by changing the waveform of voltage excitation in the working electrode. In particular, we derived a mathematical model to illustrate the principle of this method and it can also be used to demonstrate that the peak current is linear with regards to the concentration of the target substance. Moreover, we developed a device with an improved electrochemical circuit to generate the voltage excitation and detect the peak automatically. Finally, the device was used to study the electrochemical behavior of K3[Fe(CN)6]. It’s shown that the method has a better signal to noise ratio and higher sensitivity than chronoamperometry. The obtained peak current is linear with regards to the concentration of the target substance.

Abstract: Ni-Fe alloys ranging in composition of Fe rich invar (Ni100-xFeX, where x ~ 64), have a variety of high technology applications due to their wide spectrum of physical properties. In this paper, the effects of the applied potential (-1.20V, -1.35V) and the bath composition (0.1M, 0.01M) of the Ni-Fe alloy thin films are studied. Ni100-xFeX layers were electrodeposited onto Copper substrates with a pH of about 2.5. The experiments were performed at room temperature and the deposition time was equal to 10mn for all deposited samples. The experiments were performed using electrochemical techniques, by means of cyclic voltammetry (CV) and chronoamperometry (CA). The morphology and elemental composition of the deposited films were studied by means of electron microscopy coupled to EDS analysis.

Abstract: Ni-P alloy electrode was prepared by electroless plating on the Cu-Zn substrate. The surface morphology and textural properties of electrode were characterized by Scanning electron microscope(SEM), Energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD). The performance of Ni-P alloy electrode was tested by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy.The results of cyclic voltammetry showed that: At room temperature, Ni-P alloy electrode had significant catalytic effect on the electrocatalytic oxidation of ethanol in alkaline solution. Results of chronoamperometry and electrochemical impedance spectroscopy further confirmed the catalytic effect of Ni-P alloy electrode on the electrochemical oxidation of ethanol.