Electrochemical Oxidation of Ce(III) to Ce(IV) in Mixed Acid (H2SO4 and CH3SO3H)

2012 ◽  
Vol 588-589 ◽  
pp. 90-94 ◽  
Author(s):  
Hua Li Zhao ◽  
Qun Chu You ◽  
An Ma Chun

Electrochemical behaviors of Ce3+/Ce4+ couple in mixed acid (H2SO4 and CH3SO3H) were investigated on Pt electrode. Polarization curves and electrochemical impedance spectroscopy (EIS) were used to optimize mixed acid composition, and the mixed acid consisting of 1.0 M methanesulfonic acid (MSA) and 0.8 M sulfuric acid is singled out as the optimum electrolyte. Subsequently, the effects of current density and electrolyte temperature on the electrochemical oxidation of Ce3+ to Ce4+ were researched. A 92.2% current efficiency was achieved at 40 mA•cm-2 in cerium (III) solution with the optimum mixed acid electrolyte above at 313 K. It can satisfy the application of mediated electrochemical oxidation process with Ce3+/Ce4+ mediator.

2010 ◽  
Vol 132 ◽  
pp. 271-278 ◽  
Author(s):  
Dan Mei Yu ◽  
Chang Guo Chen ◽  
Shu Lei ◽  
Xiao Yuan Zhou ◽  
Guo Zhong Cao

The electrochemical oxidation of sodium borohydride (NaBH4) on Pt electrode in alkaline electrolyte with the addition of thiourea has been studied by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronopotentiometry (CP). NaBH4 is readily to react with hydroxyl groups to release hydrogen through either direct oxidation or catalytic hydrolysis. The experimental results demonstrated that the addition of an appropriate amount of thiourea to the alkaline electrolyte resulted in the suppression of catalytic hydrolysis and diffusion of borohydride ions through the separation membrane.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Belkis Ustamehmetoğlu ◽  
Nesrin Köken ◽  
Nilgun Kizilcan ◽  
Ahmet Akar ◽  
Şebnem Tayyar

Purpose The purpose of this paper is to produce non-conductive copolymers of N-vinyl carbazole (NVCz) and methyl ethyl ketone formaldehyde resin (MEKFR) by the electroinduced Ce (IV) polymerization method and the electrochemical oxidization of the formed copolymer to produce their conductive green form. The non-conductive and conductive copolymers were characterized by using Fourier transform infrared, solid-state conductivity and spectroelectrochemical, chronoamperometric, cyclovoltammetric and electrochemical impedance spectroscopic measurements. Design/methodology/approach The chronoamperometric electropolymerization of white, insulator form of the copolymer of NVCz and MEKFR (copolymer 1) on to Pt electrode was carried out and the green coloured film of the MEKFR-ox-NVCz copolymer (copolymer 11) was produced in the doped and conductive form. All reactions were performed in dichloromethane containing 0.1 M BU4NClO4. Copolymer 11 films obtained on the surface of the working electrode were removed and washed in acetonitrile and dried at room temperature before characterization. The results were compared with the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2). Findings The insulating copolymer of NVCz and MEKFR (copolymer 1) was produced by the electroinduced Ce (IV) polymerization method and converted into the conductive form electrochemically on the surface of the Pt electrode (copolymer 11). The polymers were characterized by electrochemical, spectrophotometric and conductivity measurements. The ionization potentials, optical band gap, peak potentials Ep, doping degree and specific capacitance of the copolymer 11 were obtained. The conductivity of the copolymer 11 is lower than the PNVCz and higher than the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2). The copolymer 11 has a lower onset potential than PNVCz and the copolymer 1 and slightly higher band gap than PNVCz. The capacitive behaviours of the copolymer 11 were very close to PNVCz. Research limitations/implications This study focuses on obtaining a green and conductive form of the copolymer of NVCz and MEKFR with the electrochemical method by using a white and insulator form of the same copolymer. Practical implications This work provides technical information for the synthesis of conducting copolymer of NVCz and MEKFR. Social implications These copolymers may be in the field of PNVCz applications such as photoconductivity and corrosion inhibition. Originality/value Electroinduced Ce (IV) MEKFR redox system was applied for the polymerization of NVCz monomer to produce the copolymer 1. The conductive copolymer 11 was synthesized through electrochemical oxidative coupling of the carbazole groups of the copolymer 1.


2007 ◽  
Vol 55 (1-2) ◽  
pp. 261-266 ◽  
Author(s):  
S.J. Chung ◽  
S. Balaji ◽  
M. Matheswaran ◽  
T. Ramesh ◽  
I.S. Moon

This study investigates the hybrid mediated electrochemical oxidation (HMEO) technology, which is a newly developed non thermal electrochemical oxidation process for organic destruction. A combination of ozone and ultrasonication processes to the mediated electrochemical oxidation (MEO) process is termed as hybrid mediated electrochemical oxidation. The electrochemical cell was developed in this laboratory. In the present study, several organic compounds, such as phenol, benzoquinone and ethylenediaminetetraacetic acid (EDTA), were chosen as the model organic pollutants to be destructed by the hybrid process. The organic destruction was monitored based on the CO2 generation and total organic carbon (TOC) reduction. The HMEO process was found to be extremely effective in the destruction of all the target organics chosen in this study. The information obtained from this study will provide an insight in adopting this technique for dealing with more recalcitrant organics (POPs).


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