Pt, Pt–Pd and Pt–Pd/Ru nanoparticles entrapped polyaniline electrodes – A potent electrocatalyst towards the oxidation of glycerol (original) (raw)
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Synthetic Metals, 2008
This study reports on the preparation of Pt-and Ru-based electrocatalysts through electrodeposition of Pt and Ru particles into the nanofibrous network of polyaniline (PANI)-poly(styrene sulfonic acid) (PSS). The sequence of electrodeposition of Pt and Ru particles was changed and the electrocatalysts, PANI-PSS-Pt-Ru and PANI-PSS-Ru-Pt, were obtained. Scanning electron microscopy (SEM), X-ray photoelectron microscopy (XPS), and cyclic voltammetry (CV) were employed to investigate the morphology, structural and electrochemical properties of the electrocatalysts, PANI-PSS-Pt-Ru and PANI-PSS-Ru-Pt. The distribution of Pt and Ru particles into PANI-PSS matrix was analyzed by the Auger depth profiles. The electrochemical behavior PANI-PSS-Pt-Ru and PANI-PSS-Ru -Pt and the electrocatalytic behavior toward oxidation of methanol were evaluated by cyclic voltammetry. PANI-PSS-Ru-Pt exhibited a superior electrocatalytic performance for methanol oxidation as compared to PANI-PSS-Pt-Ru.
Applied Catalysis B: Environmental, 2011
Effects toward electrocatalytic activity for glycerol oxidation of the modification of carbon supported Pd and Pt-based nanomaterials by bismuth were evaluated in alkaline medium. Pd/C, Pd 0.9 Bi 0.1 /C, Pt/C, Pt 0.9 Bi 0.1 /C and Pd 0.45 Pt 0.45 Bi 0.1 /C catalysts were synthesized by a colloidal route, and physical and electrochemical methods were used to characterize the structure and the surface of the catalysts (TEM, HRTEM, EDX, XRD, ICP-OES and XPS). It was shown that only a few amount of bismuth was deposited on the Pt and/or Pd surface, and that no alloy was formed between bismuth and the other metals. The onset potential of glycerol oxidation is ca. 0.15 V lower on Pt/C than on Pd/C. However, Pt-free Pd 0.9 Bi 0.1 /C catalyst presented the same catalytic activity than platinum catalyst. The Pt 0.9 Bi 0.1 /C led reaching a higher catalytic activity by shifting the oxidation onset potential by ca. 0.2 V toward lower potentials compared with the Pt/C catalyst. But, the replacing of half of the platinum atoms by palladium atoms in the Pd 0.45 Pt 0.45 Bi 0.1 /C material allowed achieving the same catalytic activity as with Pt 0.9 Bi 0.1 /C. Electrochemical experiments combined with in situ infrared spectroscopy measurements have shown that glycerol electrooxidation mechanism is independent on the catalyst, but dependent on the electrode potential. Chronoamperometry experiments combined with HPLC measurements showed that the main reaction products were glycerate, dihydroxyacetone and tartronate at low potentials, and that the increase of the electrode potential led to the formation of mesoxalate. For potential higher than 0.8 V vs RHE, the C-C bond cleavage occurred and oxalate and formiate were detected.
Catalytic polyaniline-supported electrodes for application in electrocatalysis
Journal of Solid State Electrochemistry, 2003
Polyaniline (Pani) films prepared on Au wires were employed as substrates to deposit Pt, Pt-Ru, Pt-Os, Pt-Mo and Pt-Ru-Os or Pt-Ru-Mo by using appropriate working solutions and a potential-programmed perturbation. The atomic percentages of the different metals on Pani were determined by EDAX and their particle size and distribution by SEM. The catalytic activity was tested for adsorbed CO and CH 3 OH electrooxidation. Accordingly, the best binary and ternary metal combination resulted in Pt-Ru and Pt-Ru-Os.
International Journal of Hydrogen Energy, 2015
The catalytic activity and stability of electrodeposited PdeCo alloy layers on Au electrode was evaluated for glycerol oxidation reaction (GOR) in an alkaline solution. The morphology and structural characteristics of the Pd and PdeCo alloy were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The electro-oxidation of glycerol on the Pd/Au and PdeCo/Au was studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) techniques. By varying Co concentration in the deposition solution, it was demonstrated that the Pd (61%)-Co (4%) catalyst [denoted PdeCo(3)/Au] has the highest electrocatalytic activity. Obtained results showed that the PdeCo(3)/Au has the excellent activity in terms of the specific peak current density and onset potential compared to pure Pd for oxidation of glycerol. For PdeCo (3)/Au, the onset potential shifts to negative values by 80 mV compared to the onset potential of Pd/Au. The stability tests indicated that the presence of Co has a significant effect on the poisoning tolerance of the Pd toward glycerol electrooxidation. Form the obtained results; one can conclude that the PdeCo alloy exhibits suitable activity as a promising catalyst for alcohol electro-oxidation reactions in fuel cells.
Polyaniline films containing palladium microparticles for electrocatalytic purposes
Journal of Solid State Electrochemistry, 2006
The deposition of palladium as microparticles on electrogenerated polyaniline (PAni) films accomplished by metal electroless precipitation or by electrodeposition has been used to prepare stable polymer-modified electrode systems. Its general morphology, metal particles size and distribution were obtained by AFM analysis. The PAni/Pd microparticles electrodes have been evaluated for their catalytic activity towards hydrogenation reactions upon organic compounds reduction using 4-nitro-benzaldehyde. Studies on rotating ring-disk electrodes have shown that relatively low Pd loadings are required to obtain effective electrocatalytic activity, provided a good metal particles dispersion of about 100 nm diameter is observed.
Electrocatalytic reduction of dioxygen at platinum particles dispersed in a polyaniline film
Electrochimica Acta, 2000
Platinum based electrocatalysts for the oxygen reduction reaction were prepared by electrodeposition of Pt particles in a polyaniline film acting as a convenient matrix to achieve low Pt loadings (from 11 to 600 mg cm − 2 ). Using a rotating disc electrode or a rotating ring disc electrode allowed us to separate the different contributions in the overall reaction : diffusion of molecular oxygen in the electrolyte solution, diffusion inside the PAni film, adsorption process, and electron transfer. Koutecky-Levich analysis made possible to evaluate the kinetics parameters (total number of exchanged electrons, limiting current density, Tafel slope and exchange current density). These parameters vary with the Pt loading, displaying a steep increase at around 200 mg.cm − 2 , above which the behavior of bulk platinum is found. At lower Pt loadings, the kinetics is controlled by a Temkin isotherm, and a large amount of hydrogen peroxide is formed.
Glycerol and Methanol Electro‐oxidation at Pt/C‐ITO under Alkaline Condition
Electroanalysis, 2016
A physical mixture composed by carbon Vulcan XC 72 and indium tin oxide (ITO) with different ratios (85 : 15; 50 : 50; 85 : 15) was used as support for platinum nanoparticles synthesis by borohydride reduction method. The characterization of this electrocatalyst was performed by transmission electron microscopy (TEM), X‐ray diffraction (XRD), electrochemical techniques cyclic voltammetry (CV), chronoamperometry and performance test on direct alkaline glycerol/methanol fuel cell (DGFC/DMFC). According to TEM micrographs, Pt/C‐ITO nanoparticles analysis revealed the presence of large agglomerations of particles. Moreover, it was possible to observe Pt deposition on ITO and also in the carbon surface. The electrochemical studies showed that Pt/C‐ITO (85 : 15) had superior performance for glycerol electro‐oxidation, whereas Pt/C‐ITO (15 : 85) was the most promising in the methanol oxidation. A comparative study using direct alkaline fuel cells revealed Pt‐C‐ITO (15 : 85) electrocatalyst...