The Effect of Platinum Nanoparticle Distribution on Oxygen Electroreduction Activity and Selectivity

Fabbri, Emiliana; Taylor, Susan M.; Rabis, Annett; Levecque, Pieter; Conrad, Olaf; Kötz, R.; Schmidt, Thomas J.

doi:10.1002/cctc.201300987

Cited by 58 publications

(91 citation statements)

References 43 publications

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“…1, and hence an overall reduction in the active Pt surface area. This effect was also observed by our groups in a study on sputtered model electrodes with increasing Pt loadings [21]. López-Cudero et al also reported on a system with increasing Pt loading on carbon (from 10 to 50 wt%) but did not observe the trend of decreasing ECSA with higher loading [27].…”

Section: Electrochemically Active Surfacesupporting

confidence: 82%

“…Hydrogen peroxide formation was seen to be greatest on the low loading, isolated platinum nanoparticle surface. Findings from this study support the presence of a serial reaction pathway for the ORR via a H 2 O 2 intermediate on a peroxide desorption-readsorption pathway [21]. Extending this study to a practical catalyst system, we here present a study based on the preparation of platinum supported on carbon catalysts by thermally induced chemical deposition with increasing platinum loadings on the support.…”

Section: Introductionsupporting

confidence: 61%

“…In a recent publication by our groups, the effect of increased platinum loading and agglomeration on the ORR and hydrogen peroxide formation was investigated for a sputtered model electrode system [21]. A decrease in the electrochemical active surface area was seen as the surface transitioned from dispersed platinum nanoparticles to an extended platinum surface.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Platinum Loading and Surface Morphology on Oxygen Reduction Activity

et al. 2016

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The catalytic activity of Pt catalysts towards the oxygen reduction reaction (ORR) was investigated on a catalyst system developed by thermally induced chemical deposition of Pt on carbon. The use of this deposition method made it possible to prepare a practical catalyst system with various Pt loadings on the support. Increasing the Pt loading caused a change in the Pt surface morphology which was confirmed by transmission electron microscopy (TEM) and CO stripping voltammetry measurements. The occurrence of a low and high-potential CO oxidation peak suggested the presence of Pt agglomerates and Pt nanoparticles, respectively. An increase in Pt loading lead to a subsequent decrease in the electrochemical surface area (ECSA, m 2 Pt /g Pt ) as the platinum surface transitioned from isolated platinum nanoparticles to platinum agglomerates. The specific activity was found to increase with increasing Pt loadings, while the mass activity decreased with loading. The mass and specific activity data from this study was found to follow a 'master curve' obtained by the comparison of normalised activities from various different studies in the literature. Pt selectivity was also affected by Pt loading and hence Pt surface morphology. At low Pt loadings, i.e. large interparticle distances, the amount of H 2 O 2 produced was significantly higher than for high Pt loadings. This confirms the presence of a 'series reaction pathway' and highlights the importance of the H 2 O 2 desorptionreadsorption mechanism on Pt nanoparticles and the ultimate role of Pt interparticle distance on the ORR mechanism.

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Section: Electrochemically Active Surfacesupporting

confidence: 82%

Section: Introductionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

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The Effect of Platinum Loading and Surface Morphology on Oxygen Reduction Activity

et al. 2016

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“…Typically, active catalysts for the HER also show good oxygen reduction reaction (ORR) performances, as has been intensively studied, such as Pt [40][41][42][43] and multi-metal catalysts. [44][45][46][47][48][49] Therefore, the evolved oxygen, which can be transported from the anode to the cathode, is reduced back to a water molecule.…”

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confidence: 99%

Electrolyte Engineering toward Efficient Hydrogen Production Electrocatalysis with Oxygen-Crossover Regulation under Densely Buffered Near-Neutral pH Conditions

Takanabe

2016

J. Phys. Chem. C

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This study tackles the core issues associated with near-neutral pH water splitting, particularly regarding electrolyte engineering in the electrocatalysis and product cross-over. The hydrogen evolution reaction (HER) was investigated on Pt, Ni and NiMo catalysts in various concentrations of cations and anions to describe their performances by quantifying kinetics and mass-transport. The choice of electrolyte in terms of its identity and activity drastically altered the HER performance. Electrolyte properties (activity coefficient, kinematic viscosity and diffusion coefficient) accurately described the mass-transport contribution, which was easily 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 isolated when a highly active Pt catalyst was used. The HER rate on the Pt was maximized by tuning the solute concentration (typically 1.5 -2.0 M). Moreover, the kinematic viscosity and oxygen solubility under such densely buffered conditions governed the oxygen mass-transport flux in the electrolyte, which in turn tuned the cross-over flux. At near-neutral pH, as high as 90 % selectivity toward the HER was achieved even under an oxygen saturated condition, where only a 40 mV overpotential was needed to achieve 10 mA cm −2 for the HER. This information can be regarded as an important milestone for achieving a highly efficient water splitting system at near-neutral pH.

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“…7 Several techniques have been explored in an attempt to produce efficient Pt electrocatalysts including chemical and physical methods such as chemical reduction [8][9][10] or sputter deposition techniques. [11][12][13] However, these techniques either lead to high metal loading with poor control of the size distribution or have proven difficult to scale up. 9,14 Although great effort has been made toward the development of chimie douce production of shape-controlled Pt nanoparticles, hierarchical nanostructures with high specific surface area remain a challenge.…”

mentioning

confidence: 99%

Electrically Bloomed Platinum Nanoflowers on Exfoliated Graphene: An Efficient Alcohol Oxidation Catalyst

Zhang

Lopes

et al. 2016

J. Electrochem. Soc.

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Platinum (Pt) based electrocatalysts have electrochemical performance that outperforms many other noble metal and metal oxide based materials. Increasing performance allows a reduction in the platinum load, and thus reduce the cost of various devices such as fuel cells. A double pulse electrochemical approach was developed to nucleate and grow Pt nanoparticles into flower shaped assemblies on graphene sheets. The unique morphology and structure of the Pt were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM). The electrocatalytical activities of the Pt nanoflowers were evaluated using methanol and ethanol oxidation as model reactions. This proposed method has led to the synthesis of Pt nanoflowers with the ability to control, both their density and their size on defect free graphene. Alternative and renewable energy sources such as hydrogen and fuel cells provide a great opportunity to overcome the challenge of pollution and energy crises.1 However, cost, performance, and durability of these energy sources are major barrier for their wide-spread commercialization. It is the key driver behind the significant research on electrocatalysts that are used for various energy devices. Carbon supports, such as carbon black, Vulcan X and Ketjen Black, are generally used as supports for electrocatalysts for electrochemical applications. These electrodes using these carbon supports, however, present some important limitations such as inadequate corrosion resistance caused by electrochemical oxidation, structural deterioration, as well as the detachment of the active metal phase. Compared to carbon black, graphene, a two-dimensional carbon nanostructure, exhibits a higher corrosion resistance, high surface area and outstanding electronic, thermal, and mechanical properties; and is anticipated to be a promising replacement for conventional carbon supports.2-4 Recently we have developed an electrochemical exfoliation approach that reproducibly produced graphene at high yield and purity with the ability to modify graphene with polystyrene sulfonate to prevent re-stacking of the sheets. 5Making Pt-based electrocatalysts more-efficient is crucial as this directly leads to less precious metal usage, i.e. lower cost.6 Attempts to optimize the platinum utilization have occurred in parallel with the development of new ways to produce Pt nanostructures with smaller size and a better Pt dispersion on the support. 7 Several techniques have been explored in an attempt to produce efficient Pt electrocatalysts including chemical and physical methods such as chemical reduction [8][9][10] or sputter deposition techniques. 11-13 However, these techniques either lead to high metal loading with poor control of the size distribution or have proven difficult to scale up.9,14 Although great effort has been made toward the development of chimie douce production of shape-controlled Pt nanoparticles, hierarchical nanostructures with high specific surface area remain a challenge. 15 Additiona...

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The Effect of Platinum Nanoparticle Distribution on Oxygen Electroreduction Activity and Selectivity

Cited by 58 publications

References 43 publications

The Effect of Platinum Loading and Surface Morphology on Oxygen Reduction Activity

The Effect of Platinum Loading and Surface Morphology on Oxygen Reduction Activity

Electrolyte Engineering toward Efficient Hydrogen Production Electrocatalysis with Oxygen-Crossover Regulation under Densely Buffered Near-Neutral pH Conditions

Electrically Bloomed Platinum Nanoflowers on Exfoliated Graphene: An Efficient Alcohol Oxidation Catalyst

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