Study of Pd–Au/MWCNTs formic acid electrooxidation catalysts

Mikolajczuk, Anna; Borodziński, Andrzej; Stobiński, Leszek; Kędzierzawski, P.; Lesiak, B.; Kövér, L.; Tóth, J.; Lin, Hong Ming

doi:10.1002/pssb.201000271

Cited by 11 publications

(25 citation statements)

References 10 publications

(42 reference statements)

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“…This may results from poisoning of metal particles surface by oligomers formed during thermal treatment in reducing (H 2 ) atmosphere from adsorbed traces of ethyl glycol. This is in agreement with the observation [4,5] that the Pd and PdAu catalysts annealed in Ar after preparation by polyol method were completely inactive. The presence of carbon residues on Pd surface may explain the lower activity of PdAu4 in comparison with PdAu2 and PdAu3, in spite of smaller PdAu crystallites found in PdAu4 sample.…”

Section: Structural Properties By Xrd and Temsupporting

confidence: 92%

“…Also, functionalised MWCNTs support decreases the agglomeration of metal nanoparticles and increases their dispersion. Recent studies on catalytic activity in formic acid electrooxidation of 17.8 wt%Pd/MWCNTs and 8.8 wt%Pd-10.0 wt%Au/MWCNTs catalysts prepared by an unmodified polyol method showed higher activity and stability for Pd-Au/MWCNTs [4,5]. The catalysts were active after reduction (5%H 2 /Ar, 200 o C), whereas inactive after annealing in ambient atmosphere (Ar, 250 o C).…”

mentioning

confidence: 95%

“…The catalysts were active after reduction (5%H 2 /Ar, 200 o C), whereas inactive after annealing in ambient atmosphere (Ar, 250 o C). The maximum cell power for Pd-Au catalyst was 26% higher than that for the Pd catalyst and much higher than of commercial 20 wt%PtRu on Vulcan support (surface area of 250 m 2 /g -producer information) catalyst [4,5]. Among series of Pd-Au/MWCNTs of different Pd:Au ratio prepared by an unmodified polyol method, the 9 wt%Pd-10 wt %Au MWCNTs supported catalyst exhibits the highest activity and stability in a direct formic acid electrooxidation in the cyclic voltammetry tests [6].…”

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confidence: 96%

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Influence of Pd‐Au/MWCNTs surface treatment on catalytic activity in the formic acid electrooxidation

Małolepszy

Mazurkiewicz

Mikolajczuk

et al. 2011

Phys. Status Solidi C

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Influence of different treatments of Pd‐Au/MWCNTs prepared by a modified polyol microwave‐assisted method on the morphology and the catalytic activity in the formic acid electrooxidation was investigated. The following standard treatments were applied to purify the metal particles surface from the carbonaceous deposits formed from ethyl glycol adsorbed on the catalyst after the preparation: 1. annealing in air at 300 °C, 2. annealing in air at 300 °C and then reduction in 5%H2/Ar at 200 °C, 3. reduction in 5%H2/Ar at 200 °C. Surprisingly, the most catalytically active sample was that without additional purification treatments. The TEM, XRD and electron spectroscopy methods were applied to characterise the catalysts. Two Pdx Au1–x phases are present in all catalysts. The treatment number 1 and 2 caused: 1. partial removing of the carbonaceous deposits from the metal surface, 2. increases metal particle sizes, 3. decreases of Pd rich phase content, 4. increases ratio of Au to Pd in the catalyst surface layer. Treatment number 4 did not change significantly the sample morphology but decreased its catalytic activity in formic acid fuel cell. It can be due oligomerization of carbon deposits during thermal treatment in reducing (H2) atmosphere (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Structural Properties By Xrd and Temsupporting

confidence: 92%

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confidence: 95%

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confidence: 96%

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Influence of Pd‐Au/MWCNTs surface treatment on catalytic activity in the formic acid electrooxidation

Małolepszy

Mazurkiewicz

Mikolajczuk

et al. 2011

Phys. Status Solidi C

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“…The specific activity of Pd in the novel Au-Pd/MWCNTs catalyst was over two times higher than that on the Pd/MWCNTs catalyst. Mikolajczuk et al [97] found that the Pd-Au/MWCNTs catalyst exhibited higher activity and more stable in oxidation reaction of formic acid. The higher initial catalytic activity of Pd-Au/MWCNTs catalyst than Pd/MWCNTs catalyst in formic acid oxidation reaction was attributed to the electronic effect of gold in Pd-Au alloy [98,99].…”

Section: Pd Alloys Supported On Carbon Nanotubesmentioning

confidence: 99%

Recent Development of Pd-Based Electrocatalysts for Proton Exchange Membrane Fuel Cells

2015

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This review selectively summarizes the latest developments in the Pd-based cataysts for low temperature proton exchange membrane fuel cells, especially in the application of formic acid oxidation, alcohol oxidation and oxygen reduction reaction. The advantages and shortcomings of the Pd-based catalysts for electrocatalysis are analyzed. The influence of the structure and morphology of the Pd materials on the performance of the Pd-based catalysts were described. Finally, the perspectives of future trends on Pd-based catalysts for different applications were considered.

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“…The carbon nanotubes (CNTs) 1 are characterized by their high specific surface area, good electrical conductivity, and access of reactants to the surface 2, and therefore their application as support for catalysts improves the catalytic performance. The Pd and Pd–Au on the multiwall carbon nanotubes (MWCNTs) supported catalysts have been recently studied 3–6. They have been found to be active in direct formic acid electrooxidation reaction for application in fuel cells (DFAFC) 3–6.…”

Section: Introductionmentioning

confidence: 99%

Ar ion bombardment modification of Pd–Au/MWCNTs catalyst surfaces studied by electron spectroscopy

Lesiak

Stobiński

Kövér

et al. 2011

Physica Status Solidi (a)

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The Pd–Au multiwall carbon nanotubes (MWCNTs) supported catalyst prepared by polyol method was found to be catalytically active material in direct formic acid fuel cell electrooxidation reaction and during cyclic voltammetry (CV) measurements. The surface of the catalyst after calcination and reduction treatments was investigated previously. The effect of Ar ion bombardment modification on the calcinated catalyst was studied by electron spectroscopy. The chemical and structural changes were deduced from the X‐ray photoelectron spectroscopy (XPS) and X‐ray excited Auger electron spectroscopy (XAES) spectra. The XPS quantitative and qualitative analysis of different chemical forms of atoms indicated that the sputtering causes an increase of Pd surface content, accompanied by decreasing content of N, O, C sp2, and Au (due to preferential sputtering of Au) and significant increase of C sp3 amount. A decrease was also observed in the surface content of (i) carboxyl groups, (ii) water, and (iii) Pd oxide (mainly less stable PdO2). Analysis of XPS inelastic background shape by QUASES indicates that Pd crystallites phase is covered by PdOx + Camorphous overlayer of decreasing thickness after sputtering. Namely, thickness of PdOx overlayer decreased from 8.2 to 3.5 nm and the thickness of amorphous carbon overlayer located on the top increased from 2.3 to 3.5 nm. Significant increase of C sp3 content results from carbon nanotube (CNT) π bonds damaging, whereas decrease of PdO2 content from lower stability of PdO2. Larger thickness of Camorphous overlayer, in contrary to PdOx, may result from higher preferential sputtering of oxygen than carbon atoms and cracking of the MWCNTs structure by Ar+ ions.

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Study of Pd–Au/MWCNTs formic acid electrooxidation catalysts

Cited by 11 publications

References 10 publications

Influence of Pd‐Au/MWCNTs surface treatment on catalytic activity in the formic acid electrooxidation

Influence of Pd‐Au/MWCNTs surface treatment on catalytic activity in the formic acid electrooxidation

Recent Development of Pd-Based Electrocatalysts for Proton Exchange Membrane Fuel Cells

Ar ion bombardment modification of Pd–Au/MWCNTs catalyst surfaces studied by electron spectroscopy

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