Irreversible structural dynamics on the surface of bimetallic PtNi alloy catalyst under alternating oxidizing and reducing environments

Khalakhan, Ivan; Vega, Lorena; Vorokhta, Mykhailo; Škála, Tomáš; Viñes, Francesc; Yakovlev, Yu. V.; Neyman, Konstantin M.

doi:10.1016/j.apcatb.2019.118476

Cited by 32 publications

(25 citation statements)

References 65 publications

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“…In the chemical ordering calculations in the larger NP 586 and NP 1289 models the last verifying step by exceedingly demanding DFT calculations was omitted, fully relying on the E TOP energies. Applications of this method [ 20 , 21 ] to various bimetallic NPs revealed that E TOP expressions despite their simplicity are sufficient for very efficient determining reliable atomic distributions in the energetically most stable homotops, in good agreement with DFT data [ 14 , 15 , 39 , 40 , 41 , 42 , 43 , 44 ].…”

Section: Computational Details and Modeling Approachmentioning

confidence: 92%

Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

et al. 2021

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Structure of model bimetallic PdAu nanoparticles is analyzed aiming to find Pd:Au ratios optimal for existence of Pd1 single-atom surface sites inside outer Au atomic shell. The analysis is performed using density-functional theory (DFT) calculations and topological approach based on DFT-parameterized topological energy expression. The number of the surface Pd1 sites in the absence of adsorbates is calculated as a function of Pd concentration inside the particles. At low Pd contents none of the Pd atoms emerge on the surface in the lowest-energy chemical orderings. However, surface Pd1 sites become stable, when Pd content inside a Pd-Au particle reaches ca. 60%. Further Pd content increase up to almost pure Pd core is accompanied by increased concentration of surface Pd atoms, mostly as Pd1 sites, although larger Pd ensembles as dimers and linear trimers are formed as well. Analysis of the chemical orderings inside PdAu nanoparticles at different Pd contents revealed that enrichment of the subsurface shell by Pd with predominant occupation of its edge positions precedes emergence of Pd surface species.

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Section: Computational Details and Modeling Approachmentioning

confidence: 92%

Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

et al. 2021

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“…Pd-Au, [13][14][15]17 Pd-Ag, 14 Pd-Cu, 14 Pd-Zn, 14 Pd-Rh, 16 Pt-Ag, 18 Pt-Co, 19,20 Pt-Ni, 21 Pt-Sn, 22 and Ni-Cu, 23 revealed efficiency and broad applicability of the TOP method. This study deals with bimetallic nanoalloys of essential for catalysis metal Pt with quite inert coinage metals Au, Ag, and Cu.…”

Section: Successfully Determined Chemical Orderings In Nps Of Various Metal Combinations Such Asmentioning

confidence: 95%

Chemical ordering in Pt–Au, Pt–Ag and Pt–Cu nanoparticles from density functional calculations using a topological approach

et al. 2021

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“…It may be attributed either to platinum alloyed with carbon [ 62 ] or to partially oxidized Pt surface due to sample exposure to air. [ 63,64 ] However, no metal–carbides at 281–283 eV [ 46 ] are present in the C 1s spectrum (see Figure 5f), suggesting that Pt δ + is associated rather with surface contamination of platinum. The C 1s spectrum in Figure 5e consists of main peak now at 284.3 eV corresponding to sp 2 ‐bonded carbon and a tail at higher binding energies that becomes more resolved due to the absence of the Ce 4s contribution.…”

Section: Resultsmentioning

confidence: 99%

A Facile Way for Acquisition of a Nanoporous Pt–C Catalyst for Oxygen Reduction Reaction

Xie

Khalakhan

Vorokhta

et al. 2021

Adv Materials Inter

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Here, the concept of preferential leaching of cerium oxide on ternary Pt–C–CeO2 compound is demonstrated in order to develop a cost‐effective catalyst for the cathode in proton exchange membrane fuel cells. The Pt–C–CeO2 thin film catalyst is prepared by simultaneous magnetron co‐sputtering of Pt, C, and CeO2. The morphology, structure, and composition of the Pt–C–CeO2 layer are characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy, and X‐ray diffraction. Both half‐cell and single‐cell tests are performed to determine its activity and durability. During an activation electrochemical cycling procedure, CeO2 is leached from the compound, leaving behind a porous Pt–C matrix which exhibits almost 3 times higher electrochemically active surface area in comparison with pure Pt with identical loading before and even after accelerated degradation tests in the half‐cell. When used as the cathode in a single‐cell membrane electrode assembly, decomposed Pt–C–CeO2 also shows greater power density than pure Pt.

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Irreversible structural dynamics on the surface of bimetallic PtNi alloy catalyst under alternating oxidizing and reducing environments

Cited by 32 publications

References 65 publications

Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

Chemical ordering in Pt–Au, Pt–Ag and Pt–Cu nanoparticles from density functional calculations using a topological approach

A Facile Way for Acquisition of a Nanoporous Pt–C Catalyst for Oxygen Reduction Reaction

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