Promotional Effect of Palladium on the Hydrogen Oxidation Reaction at a PtPd Alloy Electrode

Yoo, Sung Jong; Park, HeeYoung; Jeon, Tae‐Yeol; Park, In Soo; Cho, Yong‐Hun; Sung, Yung‐Eun

doi:10.1002/ange.200802749

Cited by 14 publications

(8 citation statements)

References 31 publications

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“…The properties of these systems are highly dependent on particle size, composition, morphology and crystal structure 5 , 6 , 20 , 21 . Recent studies have postulated that the hydrogen dissociation of Pd 1− x Pt x solid-solution alloy is proportional to the hydrogen–metal bond strength and to the d -band centre position or the d -band states near the Fermi level 22 , 23 . Furthermore, an increase of the enthalpy of metal hydride formation, a decrease of the exothermic heat has been reported, implying a decrease of the hydride stability and a decrease in the chemical bonds strength between metal and hydrogen atoms 13 , 24 .…”

Section: Introductionmentioning

confidence: 99%

Hydrogen storage and stability properties of Pd–Pt solid-solution nanoparticles revealed via atomic and electronic structure

Kumara

Sakata

Kobayashi

et al. 2017

Sci Rep

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Bimetallic Pd1−xPtx solid-solution nanoparticles (NPs) display charging/discharging of hydrogen gas, which has relevance for fuel cell technologies; however, the constituent elements are immiscible in the bulk phase. We examined these material systems using high-energy synchrotron X-ray diffraction, X-ray absorption fine structure and hard X-ray photoelectron spectroscopy techniques. Recent studies have demonstrated the hydrogen storage properties and catalytic activities of Pd-Pt alloys; however, comprehensive details of their structural and electronic functionality at the atomic scale have yet to be reported. Three-dimensional atomic-scale structure results obtained from the pair distribution function (PDF) and reverse Monte Carlo (RMC) methods suggest the formation of a highly disordered structure with a high cavity-volume-fraction for low-Pt content NPs. The NP conduction band features, as extracted from X-ray absorption near-edge spectra at the Pd and Pt LIII-edge, suggest that the Pd conduction band is filled by Pt valence electrons. This behaviour is consistent with observations of the hydrogen storage capacity of these NPs. The broadening of the valence band width and the down-shift of the d-band centre away from the Fermi level upon Pt substitution also provided evidence for enhanced stability of the hydride (ΔH) features of the Pd1−xPtx solid-solution NPs with a Pt content of 8-21 atomic percent.

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Section: Introductionmentioning

confidence: 99%

Hydrogen storage and stability properties of Pd–Pt solid-solution nanoparticles revealed via atomic and electronic structure

Kumara

Sakata

Kobayashi

et al. 2017

Sci Rep

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“…The proposed basic explanation of the ORR mechanism is that the interaction of oxygen with the surface of the catalyst involves the d-band orbital energy of the metal atoms at the surface 12 27 . Because of the absence of d-bands in the atomic valence orbitals of metal-free catalysts, the tailoring of the electrode surface is thought to be critical.…”

Section: Resultsmentioning

confidence: 99%

Facile and Gram-scale Synthesis of Metal-free Catalysts: Toward Realistic Applications for Fuel Cells

Kim

Cho

Chung

et al. 2015

Sci Rep

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Although numerous reports on nonprecious metal catalysts for replacing expensive Pt-based catalysts have been published, few of these studies have demonstrated their practical application in fuel cells. In this work, we report graphitic carbon nitride and carbon nanofiber hybrid materials synthesized by a facile and gram-scale method via liquid-based reactions, without the use of toxic materials or a high pressure-high temperature reactor, for use as fuel cell cathodes. The resulting materials exhibited remarkable methanol tolerance, selectivity, and stability even without a metal dopant. Furthermore, these completely metal-free catalysts exhibited outstanding performance as cathode materials in an actual fuel cell device: a membrane electrode assembly with both acidic and alkaline polymer electrolytes. The fabrication method and remarkable performance of the single cell produced in this study represent progressive steps toward the realistic application of metal-free cathode electrocatalysts in fuel cells.

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“…(10) and (12)]. [47,50,53] The recombination reaction or Tafel step is the rate-determining step (RDS), as reflected at low overpotentials with a measured Tafel slope of 28 mV dec À1 for the HOR in Figure 5 C (40 % Pt/CB), which is also in agreement with the findings for well-characterized polycrystalline Pt [47,54] and the theoretical value of 30 mV dec À1 obtained from Equation (10) [Eq. (13)…”

Section: Tungsten Carbide Tungsten Carbide As An Electrocatalystmentioning

confidence: 99%

Tungsten Carbide Nanoparticles as Efficient Cocatalysts for Photocatalytic Overall Water Splitting

et al. 2012

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Tungsten carbide exhibits platinum-like behavior, which makes it an interesting potential substitute for noble metals in catalytic applications. Tungsten carbide nanocrystals (≈5 nm) are directly synthesized through the reaction of tungsten precursors with mesoporous graphitic C(3)N(4) (mpg-C(3)N(4)) as the reactive template in a flow of inert gas at high temperatures. Systematic experiments that vary the precursor compositions and temperatures used in the synthesis selectively generate different compositions and structures for the final nanocarbide (W(2)C or WC) products. Electrochemical measurements demonstrate that the WC phase with a high surface area exhibits both high activity and stability in hydrogen evolution over a wide pH range. The WC sample also shows excellent hydrogen oxidation activity, whereas its activity in oxygen reduction is poor. These tungsten carbides are successful cocatalysts for overall water splitting and give H(2) and O(2) in a stoichiometric ratio from H(2)O decomposition when supported on a Na-doped SrTiO(3) photocatalyst. Herein, we present tungsten carbide (on a small scale) as a promising and durable catalyst substitute for platinum and other scarce noble-metal catalysts in catalytic reaction systems used for renewable energy generation.

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Promotional Effect of Palladium on the Hydrogen Oxidation Reaction at a PtPd Alloy Electrode

Cited by 14 publications

References 31 publications

Hydrogen storage and stability properties of Pd–Pt solid-solution nanoparticles revealed via atomic and electronic structure

Hydrogen storage and stability properties of Pd–Pt solid-solution nanoparticles revealed via atomic and electronic structure

Facile and Gram-scale Synthesis of Metal-free Catalysts: Toward Realistic Applications for Fuel Cells

Tungsten Carbide Nanoparticles as Efficient Cocatalysts for Photocatalytic Overall Water Splitting

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