Dependence of CO oxidation on Pt nanoparticle shape: a shape‐selective approach to the synthesis of PEMFC catalysts

Kinge, Sachin; Urgeghe, Christian; Battisti, Achille De; Bönnemann, Helmut

doi:10.1002/aoc.1349

Cited by 32 publications

(30 citation statements)

References 32 publications

(32 reference statements)

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“…As found on Pt single crystal electrodes, the sharp CO oxidation peak at high potentials was assigned to the CO oxidation on two-dimensional (100) terraces because this contribution well correlates with the amount and quality of the (100) domains present at the surface of the nanoparticles. The correlation between CO peak multiplicity and particle surface structure was reproduced and confirmed in other contributions by different groups [24,26]. However, CO peak multiplicity is a very controversial topic and, on non-preferentially oriented Pt nanoparticles, several explanations have been proposed to explain the origin of the peak multiplicity.…”

Section: Introductionsupporting

confidence: 65%

“…In acidic medium, CO oxidation reaction on these shape-controlled Pt nanoparticles showed a clear CO oxidation peak multiplicity that was attributed to CO oxidation from ordered (100) and (111) domains as well as from disordered surface domains [23][24][25][26]. As found on Pt single crystal electrodes, the sharp CO oxidation peak at high potentials was assigned to the CO oxidation on two-dimensional (100) terraces because this contribution well correlates with the amount and quality of the (100) domains present at the surface of the nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

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On the behavior of CO oxidation on shape-controlled Pt nanoparticles in alkaline medium

Farias

Vidal‐Iglesias

Solla-Gullón

et al. 2014

Journal of Electroanalytical Chemistry

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In this work, the behavior of the CO electro-oxidation reaction on shape-controlled Pt nanoparticles in alkaline medium was examined in order to understand the effect of the surface structure on this reaction. A series of experiments using Pt nanoparticles of different surface structures/shapes was used and the results obtained were compared with the previous knowledge gained from stepped platinum single crystal electrodes. Independently of the preferential orientation of the nanoparticles, the CO oxidation voltammetry exhibits two main peaks: one at ca. 0.56-059 V and the second one at 0.66 -0.67 V, being the intensity of the peaks dependent on the shape of the nanoparticle. These two peaks have been assigned to the oxidation of CO on the (111) terraces and on the rest of the sites, respectively. The appearance of two differentiated peaks reveals that these (111) terraces and the rest of the sites on the nanoparticle surface behave independently of the presence of the other type of sites, that is, they are not connected. The results are discussed considering the effects of the surface mobility of CO and of the OH adsorption properties on the different sites in the oxidation peaks.

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Section: Introductionsupporting

confidence: 65%

Section: Introductionmentioning

confidence: 99%

On the behavior of CO oxidation on shape-controlled Pt nanoparticles in alkaline medium

Farias

Vidal‐Iglesias

Solla-Gullón

et al. 2014

Journal of Electroanalytical Chemistry

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“…Being so, the surface structure of the nanoparticles should also affect its performance for the oxidation of CO. Understanding how the different variables affect CO oxidation on Pt nanoparticles dispersed on carbon requires the control of the platinum surface in a similar way as has been achieved for single crystal electrodes. In this sense, the influence of the surface site distribution on CO oxidation using nanoparticles of well defined shapes has been reported [6,7]. For the nanoparticle electrodes, the shape is generally more complex than that found for single crystal electrodes, since it is affected by the surface structure and nanoparticle size and aggregation.…”

Section: Introductionmentioning

confidence: 99%

CO electrooxidation on carbon supported platinum nanoparticles: Effect of aggregation

López-Cudero

Solla-Gullón

Herrero

et al. 2010

Journal of Electroanalytical Chemistry

126

121

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“…In addition, we identify a new peak (and its origin) close to the standard hydrogen electrode potential that can explain the observations in some experiments. 39,40 ■ METHODOLOGY We used the Vienna ab initio simulation package (VASP) 41,42 within a projected augmented wave (PAW) basis 43 along with the revised PBE functional 44 to obtain the DFT adsorption energies and the climbing image nudged elastic band method 45 for energy barrier calculations (details given in the Supporting Information (SI)). To compare the relative stabilities of the H* configurations, σ, on the NPs, we define the adsorption energy as As shown in Figure 1, we consider six symmetry-distinct adsorption sites 17 for H on our model 55-atom Pt cuboctahedral NP.…”

Section: ■ Introductionmentioning

confidence: 99%

Platinum Nanoparticle During Electrochemical Hydrogen Evolution: Adsorbate Distribution, Active Reaction Species, and Size Effect

et al. 2015

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For small Pt nanoparticles (NPs), catalytic activity is, as observed, adversely affected by size in the 1-3 nm range. We elucidate, via first-principles-based thermodynamics, the operation H* distribution and cyclic voltammetry (CV) during the hydrogen evolution reaction (HER) across the electrochemical potential, including the underpotential region (U ≤ 0) that is difficult to assess in experiment. We consider multiple adsorption sites on a 1 nm Pt NP model and show that the characteristic CV peaks from different H* species correspond well to experiment. We next quantify the activity contribution from each H* species to explain the adverse effect of size. From the resolved CV peaks at the standard hydrogen electrode potential (U = 0), we first deduce that the active species for the HER are the partially covered (100)-facet bridge sites and the (111)-facet hollow sites. Upon evaluation of the reaction barriers at operation H* distribution and microkinetic modeling of the exchange current, we find that the nearest-neighbor (100)-facet bridge site pairs have the lowest activation energy and contribute to ∼75% of the NP activity. Edge bridge sites (fully covered by H*) per se are not active; however, they react with neighboring (100)-facet H* to account for ∼18% of the activity, whereas (111)-facet hollow sites contribute little. Extrapolating the relative contributions to larger NPs in which the ratio of facet-to-edge sites increases, we show that the adverse size effect of Pt NP HER activity kicks in for sizes below 2 nm. KeywordsMaterials Science and Engineering, first-principles, cluster expansion, adsorption isotherm, hydrogen evolution, hydrogen oxidation, cyclic voltammetry, catalysis, platinum, electrochemistry ABSTRACT: For small Pt nanoparticles (NPs), catalytic activity is, as observed, adversely affected by size in the 1−3 nm range. We elucidate, via first-principlesbased thermodynamics, the operation H* distribution and cyclic voltammetry (CV) during the hydrogen evolution reaction (HER) across the electrochemical potential, including the underpotential region (U ≤ 0) that is difficult to assess in experiment. We consider multiple adsorption sites on a 1 nm Pt NP model and show that the characteristic CV peaks from different H* species correspond well to experiment. We next quantify the activity contribution from each H* species to explain the adverse effect of size. From the resolved CV peaks at the standard hydrogen electrode potential (U = 0), we first deduce that the active species for the HER are the partially covered (100)-facet bridge sites and the (111)-facet hollow sites. Upon evaluation of the reaction barriers at operation H* distribution and microkinetic modeling of the exchange current, we find that the nearest-neighbor (100)-facet bridge site pairs have the lowest activation energy and contribute to ∼75% of the NP activity. Edge bridge sites (fully covered by H*) per se are not active; however, they react with neighboring (100)-facet H* to account for ∼18% of the activity, wherea...

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Dependence of CO oxidation on Pt nanoparticle shape: a shape‐selective approach to the synthesis of PEMFC catalysts

Cited by 32 publications

References 32 publications

On the behavior of CO oxidation on shape-controlled Pt nanoparticles in alkaline medium

On the behavior of CO oxidation on shape-controlled Pt nanoparticles in alkaline medium

CO electrooxidation on carbon supported platinum nanoparticles: Effect of aggregation

Platinum Nanoparticle During Electrochemical Hydrogen Evolution: Adsorbate Distribution, Active Reaction Species, and Size Effect

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