Evaluation of Catalytic Activity of Pt and Pt-Ru Catalysts for Electro-oxidation of Methanol in Acid Medium by Cyclic Voltammetry

Khan, Abdul Rehman; Ahmed, Rafay; Mirza, Misbah

doi:10.4152/pea.200904429

Cited by 22 publications

(16 citation statements)

References 28 publications

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“…The above statement was verified by the linear dependency of peak current on square root of scan rate 23–27. The shift in peak potential with increase in scan rate evidenced the irreversible nature of the redox process 28.…”

Section: Resultsmentioning

confidence: 98%

“…Kinetic parameters like standard rate constant ( k s ) and apparent energy of activation ( E a ) and thermodynamic parameters including enthalpy (Δ H ) and entropy changes (Δ S ) were determined by studying the effect of temperature on square wave voltammograms of DOPQ at pH 7.0 using Equation 4 28. Current enhancement with rise in temperature was observed in SWVs shown in Figure 4.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Redox Mechanism and Evaluation of Kinetic and Thermodynamic Parameters of 1,3‐Dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline Using Electrochemical Techniques

Shah

Rana

et al. 2014

Electroanalysis

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The electrochemical behavior of a biologically important heterocyclic compound, 1,3‐dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline was investigated by cyclic, square wave and differential pulse voltammetry in solutions of different pH. Kinetic and thermodynamic parameters like standard rate constant, diffusion coefficient, apparent energy of activation, standard Gibbs free energy and enthalpy and entropy changes were evaluated. Limits of detection and quantification were determined by square wave voltammetry. The redox mechanism of the compound was proposed on the basis of experimental results. Computational chemistry was used as a tool for the verification of experimental outcomes and assessment of different theoretical parameters

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Redox Mechanism and Evaluation of Kinetic and Thermodynamic Parameters of 1,3‐Dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline Using Electrochemical Techniques

Shah

Rana

et al. 2014

Electroanalysis

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“…The irreversibility of the oxidation processes of SMPC and SNPC was ensured from the shift in peak potential with changing scan rate. 28 The diffusion coefficient for irreversible process was calculated by using Randles-Sevcik equation. 29 The D of SMPC and SNPC with values of 5.0 × 10 −6 and 1.14 × 10 −6 cm 2 s −1 were evaluated from the measured slopes (3.91 × 10 −5 and 1.8 × 10 −5 A/(V/s) 1/2 ) of the plots of I p vs. v 1/2 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Spectroscopic Characterization, pH Dependent Electrochemistry and Computational Studies of Piperazinic Compounds

Parveen

Shah

Khan

et al. 2014

J. Electrochem. Soc.

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This work presents the synthesis, redox behavior and spectroscopic characterization of two novel compounds Sodium 4-(3-methoxyphenyl) piperazine-1-carbodithioate and sodium 4-(4-nitrophenyl) piperazine-1-carbodithioate. Pulse voltammetric techniques were utilized to determine the number of electrons involved in the oxidation and/or the reduction step and to ensure the nature of the redox processes. The pH dependent redox mechanistic pathways of the compounds were proposed on the basis of electrochemical and computational results. Different thermodynamic parameters like G # and H # revealed that electrode processes are non-spontaneous and endergonic in nature. Increase in S # values at higher temperature indicated the randomness of the electrode reactions at higher temperatures. Limits of detection and quantification were determined by square wave voltammetry due to its high sensitivity and fast speed. Ionization energy, electron affinity, dipole moment and charge distribution on atoms were computationally determined. Acid-base dissociation constant (pKa) values of the compounds evaluated by voltammetry and electronic spectroscopy were found comparable. Molecular architectures bearing piperazine group have gained the utmost attention due to their vast applications in medical and industrial fields. Piperazines have special importance among nitrogen containing heterocyclic compounds due to their hydrogen bonding ability that make such compounds very specific for the generation of supramolecular structures.1 Piperazine can exhibit chair or boat conformation with chair form being more stable by 17.2 kJ/mol.2 Compounds containing piperazine ring are used as raw materials for the synthesis of epoxy resins, antioxidants, urethane catalysts, insecticides and accelerators for rubber.3 Such compounds possess versatile binding properties and act as potent and selective ligands for different biological activities. The attachment of piperazine to porphrin ring has been reported to enhance the anticancer activity and play the role of sensitizer in photodynamic therapy.4-8 Piperazine derivatives show good activities against chloroquine resistant strain of Plasmodium falciparum in vitro with low toxicity against murine monocyte/macrophage cells.9 Such compounds are also used as chelating agents due to their ability of forming complex with metal ions. Free radicals formation in many bioorganic redox processes may result in oxidation of lipids, proteins, or DNA and thus initiate cancer, cardiovascular, autoimmune, inflammatory and age-related degenerative brain diseases. So, piperazine as reducing agent is gaining mounting attention due to free radicals scavenging ability. 10 Dithio ligands have been documented to play vital roles in numerous biological and non-biological processes.11-13 Dithiocarbamate (DTC) derivatives are used as organic intermediates, vulcanizing agents, rubber additives and fungicides.14 DTC a putative immunomodulator plays pivotal roles in agriculture and enhances immune response in AIDS treatment. 15 Comple...

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“…It can be clearly noted that the electrooxidation of methanol is enhanced with increasing the scan rate of the applied potential which con¯rms that the electrocatalytic oxidation of methanol on Co/Cr CNFs is controlled by di®usion-controlled process. 49,50 It is noteworthy to mention that all the aforementioned results are related to 10 wt.% Cr in Cr/ Co composition. To study the e®ect of Cr content, several compositions have been prepared.…”

Section: -5mentioning

confidence: 99%

Cobalt/Chromium Nanoparticles-Incorporated Carbon Nanofibers as Effective Nonprecious Catalyst for Methanol Electrooxidation in Alkaline Medium

Mohamed

Motlak

Fouad

et al. 2016

NANO

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Cobalt-Chrome nanoparticles-incorporated carbon nano¯bers (CNFs) are proposed as an e®ec-tive nonprecious electrocatalyst for methanol oxidation in the alkaline media. The introduced nano¯bers were prepared by simple technique, electrospinning. Carbonization of as-spun mat composed of chromium acetate, cobalt acetate and poly(vinyl alcohol) (PVA) at high temperature (900 C) leads to production of the introduced nano¯bers. The physicochemical characteristics were investigated by X-ray di®ractometer (XRD), scanning electron microscope (SEM), eld emission scanning electron microscope (FESEM), transmission electron microscope (TEM) equipped with EDX and TEM mapping. The exploited analyses con¯rmed that the¯nal product is in the form of CNFs decorated by Co/Cr nanoparticles. Based on the results obtained from the cyclic voltammetry (CV) measurements, the proposed Co/Cr-incorporated CNFs possess high electrocatalytic activity toward methanol electrooxidation as a clear peak of methanol oxidation appeared with corresponding current density of 56 mA/cm 2 . Moreover, the current density increased by increasing methanol concentration up to 4.0 M. Overall, the proposed nano¯bers open new avenue for platinum-free and stable nanostructural catalysts for fuel cell technology.

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Evaluation of Catalytic Activity of Pt and Pt-Ru Catalysts for Electro-oxidation of Methanol in Acid Medium by Cyclic Voltammetry

Cited by 22 publications

References 28 publications

Redox Mechanism and Evaluation of Kinetic and Thermodynamic Parameters of 1,3‐Dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline Using Electrochemical Techniques

Redox Mechanism and Evaluation of Kinetic and Thermodynamic Parameters of 1,3‐Dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline Using Electrochemical Techniques

Synthesis, Spectroscopic Characterization, pH Dependent Electrochemistry and Computational Studies of Piperazinic Compounds

Cobalt/Chromium Nanoparticles-Incorporated Carbon Nanofibers as Effective Nonprecious Catalyst for Methanol Electrooxidation in Alkaline Medium

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