On the preparation methods for carbon nanofiber-supported Pt catalysts

Kvande, Ingvar; Briskeby, Stein Trygve; Tsypkin, Mikhail; Rønning, Magnus; Sunde, Svein; Tunold, R.; Chen, De

doi:10.1007/s11244-007-0244-5

Cited by 36 publications

(36 citation statements)

References 17 publications

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“…49 The diameter of a Pt 100 cluster is ∼2 nm, which is within the cluster size investigated experimentally for fuel cell catalysis applications (i.e., 1-5 nm). 5,7,50 The initial structure of the Pt 100 cluster was found by an energy minimization based on a genetic algorithm (GA). 51 The carbon platelets were built by creating a small graphite slab with a distance of 1.42 Å between carbon atoms within each graphitic layer, which is the distance between first neighbor atoms in graphite.…”

Section: Reactive Force Fieldsmentioning

confidence: 99%

Molecular Dynamics Simulations of the Interactions between Platinum Clusters and Carbon Platelets

et al. 2008

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Molecular dynamics simulations have been performed with two reactive force fields to investigate the structure of a Pt 100 cluster adsorbed on the three distinct sides of a carbon platelet. A revised Reax force field for the carbon-platinum system is presented. In the simulations, carbon platelet edges both with and without hydrogen termination have been studied. It is found that the initial mismatch between the atomic structure of the platelet egde and the adsorbed face of the Pt 100 cluster leads to a desorption of a few platinum atoms from the cluster and the subsequent restructuring of the cluster. Consequently, the average Pt-Pt bond length is enlarged in agreement with experimental results. This change in the bond length is supposed to play an important role in the enhancement of the catalytic activity, which is demonstrated by studying the changes in the bond order of the platinum atoms. We found an overall shift to lower values as well as a loss of the well-defined peak structure in the bond-order distribution.

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Section: Reactive Force Fieldsmentioning

confidence: 99%

Molecular Dynamics Simulations of the Interactions between Platinum Clusters and Carbon Platelets

et al. 2008

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“…In our case, a colloidal Pt solution was dropped onto a carbon coated TEM grid. The colloidal solution is likely to contain Pt of higher valences in the form of PtCl [2][3][4][5][6] or in citrate complexes. Guo et al 13 and Henglein 17 have observed Pt of higher valence state when using the citrate stabilized synthesis methods.…”

Section: Discussionmentioning

confidence: 99%

“…% in order to achieve thin active electrode layers minimizing mass transport limitations and ohmic resistance 2 Tunold, 1933Tunold, -2013 (HDP), impregnation and deposition of colloidal particles. 5,6 The former two methods are limited to low loading catalysts 2 . High loadings are readily achieved by impregnation.…”

Section: Introductionmentioning

confidence: 99%

Preparation of electrocatalysts by reduction of precursors with sodium citrate

et al. 2014

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In this work synthesis of Pt/C catalysts by reduction of H 2 PtCl 6 with sodium citrate has been investigated. The strong pHdependence of citrate as a reducing and stabilizing agent has been explored, and an optimum pH range for production of well dispersed catalysts is proposed. To achieve stabilizing and reducing conditions, the presence of both citrate anions and protonated citrates are required. This is achieved in an intermediate pH range between pK a2 and pK a3 (4.76 and 6.4) of citric acid, where both C 6 H 5 O 3-7 (denoted CA 3-) and C 6 H 7 O -6 (denoted H 2 CA -) are present. At pH 5.3-5.4 a catalyst with particles around 3 nm was thus successfully prepared. At high pH (∼12) the reduction of Pt is limited, whereas at low pH reduction is fast, but the stabilizing ability of the citrate in solution is poor resulting in large cubic Pt particles. CO-stripping voltammetry indicate that Pt(111) faces are the dominating crystal plane in the nanoparticles formed when citrate anions are used as stabilizing agent. This effect is presumably caused by the distance between oxygen groups in citrate correlating well with the Pt-Pt distance on (111) faces.

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“…A modified polyol method [25,26] was used for preparation of a 10 wt. % Pt catalyst on platelet carbon nanofibre support.…”

Section: Methodsmentioning

confidence: 99%

Stability of carbon nanofibre-supported platinum catalysts in the presence of chloride under controlled mass-transfer conditions

Briskeby

Tsypkin

Tunold

et al. 2014

Journal of Power Sources

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The effect of chloride on the stability of platinum electrocatalysts was studied by rotating disk measurements in sulfuric acid electrolyte with a continuously increasing concentration of chloride anions. The activity towards oxygen reduction was found to be reduced by a factor of seven when 140 ppm chloride was present. Platinum corrosion was severe at high potentials, presumably accelerated by potential cycling, and greatly enhanced by mass transport. A five-fold increase in corrosion rate was found when the electrode was rotated at 1600 rpm with respect to stagnant conditions. At potentials where oxygen reduction occurs, dissolved Pt can be redeposited on the electrode. The Pt dissolution rate increased with increasing Cl -concentration up to 20 ppm. Above this threshold the corrosion rate was unaffected by increases in Cl -content.

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On the preparation methods for carbon nanofiber-supported Pt catalysts

Cited by 36 publications

References 17 publications

Molecular Dynamics Simulations of the Interactions between Platinum Clusters and Carbon Platelets

Molecular Dynamics Simulations of the Interactions between Platinum Clusters and Carbon Platelets

Preparation of electrocatalysts by reduction of precursors with sodium citrate

Stability of carbon nanofibre-supported platinum catalysts in the presence of chloride under controlled mass-transfer conditions

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