Electrocatalytic Oxidation of Ethanol at Pd/PANI Electrocatalyst

2013 ◽  
Vol 11 (2) ◽  
Author(s):  
M. A. Ibrahim
Keyword(s):  
Electrocatalytic Oxidation ◽  
Ethanol Oxidation ◽  
Mass Ratio ◽  
Direct Ethanol Fuel Cells ◽  
Cyclic Voltammetric ◽  
Transmission Electron ◽  
Voltammetric Measurement ◽  
Microscopy Techniques ◽  
Oxidation Of Ethanol ◽  
Cyclic Voltammetric Measurement

Palladium Pd/polyaniline (PANI) nanocomposite was prepared by a thermal reflux method as the catalyst for direct ethanol fuel cells. The Pd/PANI catalysts were characterized by using FTIR transmission electron microscopy techniques. The electrocatalytic performances of Pd/PANI catalysts for ethanol oxidation were studied by cyclic voltammetric measurement. It was found that, compared with Pd, the Pd/PANI catalyst showed superior electrocatalytic activity for ethanol oxidation when the mass ratio of Pd precursor salt to PANI was about 1:2.

Thermodynamic Study of Ce4+ /Ce3+ Redox Reaction in Aqueous Solutions at Elevated Temperatures: 1. Reduction Potential and Hydrolysis Equilibria of Ce4+ in HCIO4 Solutions

1992 ◽  
Vol 47 (9) ◽  
pp. 974-984 ◽  
Author(s):  
B. A. Bilal ◽  
E. Müller
Keyword(s):  
Redox Reaction ◽  
Elevated Temperatures ◽  
Formation Constants ◽  
Cyclic Voltammetric ◽  
Voltammetric Measurement ◽  
Constant Potential ◽  
Increasing Temperature ◽  
Aqueous Hclo ◽  
Stepwise Formation ◽  
Cyclic Voltammetric Measurement

AbstractThe redox potential (E) of the couple Ce4+/Ce3+ has been determined up to 368 K by means of cyclic voltammetric measurement in aqueous HClO4 solutions with cHClO4 decreasing from 7.45 to 0.023 mol kg-1 . A constant potential of (1.741 V)298 K, resp. (1.836 V)368K, indicating the existence of pure unhydrolysed Ce4+ was obtained at cHClO4 ≥ 6.05 m. At lower HClO4 concentration, the potential as a function of the HClO4 molality, as well as of the pH shows 4 further distinct steps. At 298 K, for instance, the potential became nearly constant at pH values of 0.103, 0.735,1.115, after which it drastically decreased, respectively at 1.679, just before the precipitation of Ce(OH)4 occurred. The curves indicate obviously the stepwise formation of the Ce(IV) mono-, di-, tri- and tetrahydroxo complexes. The slope of the curves E vs. pH increased gradually with increasing temperature. ΔS and ΔH of the redox reaction were determined as functions of T at the different HClO4 concentrations. ΔSis positive at cHClO4 > 1.85 m and turns to be negative at lower concentrations. ΔHis negative at all HClO4 concentrations studied. The cumulative formation constants ßi, of the Ce(IV) hydroxo complexes and the corresponding hydrolysis constants (Kh)i were calculated. An unusual decrease of ßi with increasing temperature has been discussed

scholarly journals Electrocatalytic oxidation of ethanol at Pd, Pt, Pd/Pt and Pt/Pd nano particles supported on poly 1,8-diaminonaphthalene film in alkaline medium

RSC Advances ◽  
2018 ◽  
Vol 8 (28) ◽  
pp. 15417-15426 ◽  
Author(s):  
K. M. Hassan ◽  
A. A. Hathoot ◽  
R. Maher ◽  
M. Abdel Azzem
Keyword(s):  
Alkaline Medium ◽  
Oxidation Reaction ◽  
Electrocatalytic Oxidation ◽  
Ethanol Oxidation ◽  
Pt Nanoparticles ◽  
Nano Particles ◽  
Composite Catalyst ◽  
Ethanol Oxidation Reaction ◽  
Oxidation Of Ethanol

An ethanol oxidation reaction (EOR) in alkaline medium was carried out at palladium (Pd) or platinum (Pt) nanoparticles/poly 1,8-diaminonaphthalene (p1,8-DAN) composite catalyst electrodes.

A Review of Pd-Based Electrocatalyst for the Ethanol Oxidation Reaction in Alkaline Medium

2013 ◽  
Vol 860-863 ◽  
pp. 826-830 ◽  
Author(s):  
Long Long Wang ◽  
Qiao Xia Li ◽  
Tian Yu Zhan ◽  
Qun Jie Xu
Keyword(s):  
Alkaline Medium ◽  
Oxidation Reaction ◽  
Ethanol Oxidation ◽  
Synthetic Methods ◽  
Alkaline Media ◽  
Complete Oxidation ◽  
Ethanol Oxidation Reaction ◽  
Direct Ethanol Fuel Cells ◽  
In Situ Ftir Spectroscopy ◽  
Oxidation Of Ethanol

Direct ethanol fuel cells are considered a promising power source for future portable electronic and automotive applications. This article reviewed the synthetic methods commonly used to prepare Pd-based catalysts for the ethanol electrooxidation in alkaline media. The progress in the mechanism studies of ethanol oxidation reaction (EOR) on Pd electrode in alkaline medium by cyclic voltammetry and electrochemical in situ FTIR spectroscopy was also reviewed. The recent studies revealed that the EOR is fairly complicated, and it is difficult in CC bond cleavage for the complete oxidation of ethanol to CO2, and ethanol is selectively oxidized to acetate on Pd-based catalysts in alkaline media. Overall, what is most important is to explore new Pd-based alloy catalysts with high ability to break the CC bond to promote complete oxidation of ethanol as well as increase the efficiency of DEFCs.

Testing Different Catalysts for a Vapor-Fed PBI-Based Direct Ethanol Fuel Cell

2009 ◽  
Author(s):  
J. Lobato ◽  
P. Can˜izares ◽  
M. A. Rodrigo ◽  
J. J. Linares ◽  
B. Sa´nchez-Rivera
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Low Temperature ◽  
Ethanol Oxidation ◽  
Ethanol Fuel ◽  
Direct Ethanol Fuel Cells ◽  
Direct Ethanol Fuel Cell ◽  
High Temperature Operation ◽  
High Ethanol ◽  
Oxidation Of Ethanol

With the aim of improving the ethanol oxidation in fuel cells, researchers have developed numerous catalysts to break up the C-C bond. Most of the tests have been carried out at low temperature, using Nafion membrane as electrolyte. The cell performance of the Direct Ethanol Fuel Cells (DEFCs) at low temperature is still far from its industrial application. To improve the DEFC power density, high temperature operation (150–200 °C) has been suggested to promote the complete oxidation of ethanol. Thus, three different catalysts (Pt-Ru (1:1), Pt-Sn (1:1) and Pt-Sn-Ru (1:1:0.3), all of them supported on both non-activated and activated carbon were tested in H3PO4 doped PBI-based fuel cell, using vapour fed ethanol, operating in the range of 150–200 °C, and high ethanol concentration 6.7 M. The catalyst were synthesized using NaBH4 as reducing agent and were characterized by XRD, ICP-AES and TPR analyses. The best performance was reached at the highest temperature and with the catalyst based on Pt-Ru. The best results for the Ru-based catalyst can be explained by the higher level of alloying reached for the Ru than for Sn, which modifies the crystalline structure of Pt and enhances the activity oxidation of ethanol and of intermediates that are generated during the oxidation of ethanol.

Nanoscale Structural and Chemical Segregation in Pt50Ru50 Electrocatalysts

2001 ◽  
Vol 7 (S2) ◽  
pp. 1112-1113
Author(s):  
Rhonda M. Stroud ◽  
Jeffrey W. Long ◽  
Karen E. Swider-Lyons ◽  
Debra R. Rolison
Keyword(s):  
Methanol Oxidation ◽  
Structural Heterogeneity ◽  
Oxidation Activity ◽  
Bimetallic Alloy ◽  
Transmission Electron ◽  
Chemical Segregation ◽  
High Fraction ◽  
Argon Mixture ◽  
Microscopy Techniques ◽  
Electron Energy Loss

To address how the chemical and structural heterogeneity of Pt50Ru50 nanoparticles affects methanol oxidation activity, we have employed an arsenal of transmission electron microscopy techniques (conventional bright field-imaging, selected area diffraction, atomic-resolution lattice imaging, electron-energy loss spectroscopy, and energy-dispersive x-ray spectroscopy) to characterize 2.5-nm particles in differing oxidation and hydration states. Our studies demonstrate that electrocatalysts containing a high fraction of Ru-rich hydrous oxide, as apposed to the anhydrous PtRu bimetallic alloy, have as much as 250x higher methanol oxidation activityThe nominally 2.5-nm Pt50Ru50 particles were studied in as-received, reduced and reoxidized forms. The reducing treatment consisted of 2 h at 100 °C in flowing 10% PL/argon mixture. For re-oxidation, the reduced particles were heated for 20 h at 100 °C in an H2O-saturated oxygen atmosphere. The particles were suspended in methanol, and pipetted onto holey-carboncoated Cu grids for TEM studies.

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