Nanostructured Pt and Pt–Sn catalysts supported on oxidized carbon nanotubes for ethanol and ethylene glycol electro-oxidation

Sieben, Juan Manuel; Duarte, Marta María Elena

doi:10.1016/j.ijhydene.2010.12.020

Cited by 113 publications

(73 citation statements)

References 59 publications

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“…On the other hand, although the full oxidation of ethanol to carbon dioxide has a favorable thermodynamic potential of 0.08 V (vs. RHE), the efficiency of direct ethanol fuel cells is already severally limited by the formation of partial oxidation products (containing an intact carbon-carbon bond) and strongly adsorbed intermediates. The great body of work developed in the last few years indicates that various Pt-based catalysts such as PtSn [11][12][13] or PtRu [14][15][16] display enhanced electrocatalytic performance for ethanol electrooxidation with respect to monometallic Pt catalyst. In both reactions, the use of oxophilic atoms can aid in the oxidation of CO from the surface as they enhance the activation of water to form surface hydroxides, which can more readily oxidize CO and CH x intermediates that form via bifunctional pathways [17,18].…”

Section: Introductionmentioning

confidence: 99%

Carbon-Supported PtRuMo Electrocatalysts for Direct Alcohol Fuel Cells

et al. 2013

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Abstract:The review article discusses the current status and recent findings of our investigations on the synthesis and characterization of carbon-supported PtRuMo electrocatalysts for direct alcohol fuel cells. In particular, the effect of the carbon support and the composition on the structure, stability and the activity of the PtRuMo nanoparticles for the electrooxidation of CO, methanol and ethanol have been studied. Different physicochemical techniques have been employed for the analysis of the catalysts structures: X-ray analytical methods (XRD, XPS, TXRF), thermogravimetry (TGA) and transmission electron microscopy (TEM), as well as a number of electrochemical techniques like CO adsorption studies, current-time curves and cyclic voltammetry measurements. Furthermore, spectroscopic methods adapted to the electrochemical systems for in situ studies, such as Fourier transform infrared spectroscopy (FTIRS) and differential electrochemical mass spectrometry (DEMS), have been used to evaluate the oxidation process of CO, methanol and ethanol over the carbon-supported PtRuMo electrocatalysts.

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Section: Introductionmentioning

confidence: 99%

Carbon-Supported PtRuMo Electrocatalysts for Direct Alcohol Fuel Cells

et al. 2013

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“…Aiming to solve this problem researchers are developing new bi and/or trimetallic catalysts for the complete oxidation of ethylene glycol [3,8]. The alloys are seen as more tolerant to the CO poisoning, since the presence of a second or third metal as co-catalyst modifies the atomic structure and the valence of the d orbitals of the Pt [21,22,23]. These co-catalysts weaken the adsorption energy of CO and facilitate the cleavage of the C-C bond of the adsorbed alcohols [21,22,23].…”

Section: Introductionmentioning

confidence: 99%

Ethylene glycol oxidation on ternary PtRhNi/C electrocatalyst with different metal compositions

Marinho¹,

Pocrifka

Passos

2017

Matéria (Rio J.)

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Direct Alcohol Fuel Cells (DAFC's) are an alternative to fuel cell systems and when is used alkaline medium this has an increase performance. The alkaline direct alcohol fuel cells (ADAFC's) have some advantages such as low-emission, high energy efficiency, improved oxidation kinetics, low crossover and in addition there is a broad range of materials that can be used as catalysts. The ethylene glycol (EG) has received attention in recent decades as an alternative fuel for ADAFC, but like others alcohols must be completed oxidized to generate full power energy. In this study we analyzed ternary PtRhNi/C electrocatalysts with different compositions, synthesized by alcohol reduction method, and compared to Pt/C ETEK. The active area, catalytic activity and stability of catalysts for ethylene glycol oxidation in alkaline medium were studied by cyclic voltammetry, CO stripping voltammetry and chronoamperometry tests. XRD technique was applied to physical characterization and it was observed the formation of alloy. The average crystallite size was calculated from the Scherrer equation. The Pt 92 Rh 7 Ni 1 /C electrocatalyst shows a larger electrochemically active area and consequently higher catalytic activity for EG oxidation. This response was attributed to improvement in the synergistic effect provided by the reduction of the amount of Rh and Ni in the ternary alloy when compared to Pt 80 Rh 15 Ni 5 /C and Pt/C ETEK electrocatalysts. However, Pt 80 Rh 15 Ni 5 /C electrocatalyst showed greater tolerance to poisoning by intermediate species due to the presence of Rh in greater quantity, leading to a formation of adsorbed OH species in potentials smaller than those for platinum.

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confidence: 99%

“…The electrochemical oxidation of EG on the Pt/C catalyst in acid media has attracted interest because of its potential application as a fuel for direct alcohol fuel cells. [17][18][19][20][21][22][23][24][25] In addition to the complete oxidation product CO 2 , the electro-oxidation of EG produces numerous stable, adsorbed species and partly oxidized by-products such as adsorbed CO, glycolic acid, oxalic acid, glycolaldehyde, glyoxal, glyoxylic acid, formaldehyde, and formic acid. [18][19][20][21][22][23][24] The adsorbed CO and oxidation by-products block the Pt active sites, which results in a performance loss for both ORR and HOR.…”

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confidence: 99%

Effects of Ethylene Glycol and Caprolactam on the ORR and HOR Performances of Pt/C Catalysts

Zhai

St‐Pierre

2016

J. Electrochem. Soc.

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Ethylene glycol (EG) and caprolactam are two representative contaminant species either present in the fuel cell system or released by fuel cell system materials. The contamination effects of EG and caprolactam on the electro-catalytic performances of a Pt/C catalyst toward the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) were investigated in acid media using the rotating ring/disk electrode (RRDE) technique. The Pt surface coverage increased with EG and caprolactam concentrations. The H 2 O 2 yield also significantly increased because of the effects of the two contaminants. The EG-and caprolactam-derived adsorbates reduce the ORR and HOR rates and modify the rate-determining step (change in Tafel Considering the inevitable depletion of conventional fossil fuels and the release of greenhouse gases into the Earth's atmosphere, it is necessary to look for renewable and clean energy supplies. Proton exchange membrane fuel cells (PEMFCs) are promising as clean energy sources for future automotive applications. However, the performance and durability of PEMFCs can be significantly decreased by the presence of contaminants in air and hydrogen or released by fuel cell system materials.1-3 Such species may adsorb on the Pt catalyst, penetrate into the ionomer and membrane, or compete with the main reactions, which decreases the active surface area, ionic conductivity of the catalyst layer and membrane, and cell performance. 2,4-9In addition, H 2 O 2 , which is a side product of the oxygen reduction reaction (ORR), and its associated yield often increases in the presence of organic contaminants such as acetylene, acetonitrile, propene, naphthalene, and methyl methacrylate. 10-13 A larger H 2 O 2 generation rate exerts an undetermined effect on the performance and durability of PEMFCs. The formation of H 2 O 2 has been linked to the radical attack decomposition of the Nafion ionomer, which is accelerated by the presence of Fe 2+ and Cu 2+ ions. 14,15 The Nafion ionomer is used as an electrolyte membrane and added to the catalyst layer to exploit its binding property and improve catalyst utilization. Consequently, the decomposition of the Nafion ionomer is a significant risk to the PEMFC performance and durability. Therefore, it is necessary to investigate the ORR, hydrogen oxidation reaction (HOR), and H 2 O 2 yield in the presence of contaminants to understand their effects on PEMFCs.This study was initiated with a list of system contaminants identified by the National Renewable Energy Laboratory (NREL).16 These were separated into 2 classes: linear and more structurally complex molecules including cyclic molecules (ring-shaped). One molecule of each class was chosen for these initial studies. Ethylene glycol (EG) is interesting because it is widely used as a coolant, antifreeze agent, and de-icing solution. De-icing of airport runways and airplanes is the primary source of EG in the environment. EG is also dispersed in the environment by the disposal of products that contain it. In addition, 1,6...

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Nanostructured Pt and Pt–Sn catalysts supported on oxidized carbon nanotubes for ethanol and ethylene glycol electro-oxidation

Cited by 113 publications

References 59 publications

Carbon-Supported PtRuMo Electrocatalysts for Direct Alcohol Fuel Cells

Carbon-Supported PtRuMo Electrocatalysts for Direct Alcohol Fuel Cells

Ethylene glycol oxidation on ternary PtRhNi/C electrocatalyst with different metal compositions

Effects of Ethylene Glycol and Caprolactam on the ORR and HOR Performances of Pt/C Catalysts

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