Physical properties of the GaPd2 intermetallic catalyst in bulk and nanoparticle morphology

Wencka, Magdalena; Schwerin, J.; Klanjšek, M.; Krnel, Mitja; Vrtnik, S.; Koželj, Primož; Jelen, Andreja; Kapun, Gregor; Jagličić, Zvonko; Sharafutdinov, Irek; Chorkendorff, Ib; Gille, Peter; Dolinšek, J.

doi:10.1016/j.intermet.2015.07.010

Cited by 5 publications

(6 citation statements)

References 27 publications

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“…A nonzero intensity at E F remains in Pd 2 Ga and leads to a metal-type behavior of this alloy. The low-intensity features below the main valence band of Pd 2 Ga are due to Pd 5s and Ga 4s states . The Pd 3 d 5/2 core level maximum of the mixed Pd/Ga samples lies at 335.6 eV, which is in accordance with previously reported values for the formation of the Pd 2 Ga alloy. ,, …”

Section: Resultssupporting

confidence: 90%

Pd₂Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO₂ to Methanol

García‐Trenco

White²,

Regoutz³

et al. 2017

ACS Catal.

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Colloidal Pd2Ga-based catalysts are shown to catalyze efficiently the hydrogenation of CO2 to methanol. The catalysts are produced by the simple thermal decomposition of Pd(II) acetate in the presence of Ga(III) stearate, which leads to Pd0 nanoparticles (ca. 3 nm), and the subsequent Pd-mediated reduction of Ga(III) species at temperatures ranging from 210 to 290 °C. The resulting colloidal Pd2Ga-based catalysts are applied in the liquid-phase hydrogenation of carbon dioxide to methanol at high pressure (50 bar). The intrinsic activity is around 2-fold higher than that obtained for the commercial Cu-ZnO-Al2O3 (60.3 and 37.2 × 10–9 molMeOH m–2 s–1), respectively, and 4-fold higher on a Cu or Pd molar basis (3330 and 910 μmol mmolPd or Cu–1 h–1). Detailed characterization data (HR-TEM, STEM/EDX, XPS, and XRD) indicate that the catalyst contains Pd2Ga nanoparticles, of average diameters 5–6 nm, associated with a network of amorphous Ga2O3 species. The proportion of this Ga2O3 phase can be easily tuned by adjusting the molar ratio of the Pd:Ga precursors. A good correlation was found between the intrinsic activity and the content of Ga2O3 surrounding the Pd2Ga nanoparticles (XPS), suggesting that methanol is formed by a bifunctional mechanism involving both phases. The increase in the reaction temperature (190–240 °C) leads to a gradual decrease in methanol selectivity from 60 to 40%, while an optimum methanol production rate was found at 210 °C. Interestingly, unlike the conventional Cu-ZnO-Al2O3, which experienced approximately 50% activity loss over 25 h time on stream, the Pd2Ga-based catalysts maintain activity over this time frame. Indeed, characterization of the Pd/Ga mixture postcatalysis revealed no ripening of the nanoparticles or changes in the phases initially present

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Section: Resultssupporting

confidence: 90%

Pd₂Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO₂ to Methanol

García‐Trenco

White²,

Regoutz³

et al. 2017

ACS Catal.

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“…Intermetallic compounds have ordered crystal structures that differ from their elemental constituents. Meanwhile, the electronic structure of intermetallic catalysts, which has a strong influence on the adsorption properties and surface reactivity of the compound, can also be very different from those of the elemental constituents . Many experimental studies have revealed that the formation of intermetallic active components on supported Pd catalysts, such as Pd/ZnO, − Pd/In 2 O 3 , − and Pd/Ga 2 O 3 , ,,− is capable of improving their catalytic performance in the process of semihydrogenation, methanol steam reforming, and methanol synthesis reactions.…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, the electronic structure of intermetallic catalysts, which has a strong influence on the adsorption properties and surface reactivity of the compound, can also be very different from those of the elemental constituents. 7 Many experimental studies have revealed that the formation of intermetallic active components on supported Pd catalysts, such as Pd/ZnO, 8−12 Pd/In 2 O 3 , 13−15 and Pd/Ga 2 O 3 , 11,12,16−19 improving their catalytic performance in the process of semihydrogenation, methanol steam reforming, and methanol synthesis reactions. Iwasa et al reported that, compared with the pure metallic Pd catalyst, catalysts composed of Pd or Pt supported on ZnO, Ga 2 O 3 , and In 2 O 3 are highly selective in methanol steam reforming, which could be attributed to the formation of Pd-or Pt-based alloys.…”

Section: Introductionmentioning

confidence: 99%

Role of Surface Species Interactions in Identifying the Reaction Mechanism of Methanol Synthesis from CO₂Hydrogenation over Intermetallic PdIn(310) Steps

Zaffran

Yang

2019

J. Phys. Chem. C

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Considerable attention has been paid to the development of new catalysts for methanol synthesis from CO 2 hydrogenation for a long period of time. The PdIn intermetallic catalyst was found recently to exhibit good stability and activity for methanol formation. We thus performed a theoretical study to understand the reaction mechanism of methanol synthesis on stepped PdIn(310), combining density functional theory (DFT) calculations and microkinetic analysis. On the basis of energetics obtained on clean PdIn(310), we found that the preferred reaction pathway for CH 3 OH generation proceeds through the COOH intermediate and further CO hydrogenation. However, microkinetic results suggested that the coverage of formate and carbon monoxide at the steady state is nearly one monolayer at the corresponding preferred adsorption site, that is, the In site for HCOO and the Pd site for CO, within the whole temperature range studied. Therefore, further studies were carried out to reveal the influence of coverage of preadsorbed formate and carbon monoxide on adsorption energies. It turned out that the differential adsorption energy of formate at the In site is comparable to that at the Pd site when the surface is covered by two formate at the In step-bridge site, indicating that it is possible for an additional formate to adsorb at either the Pd or In site under such condition. On this basis, we found with further DFT calculations and microkinetic analysis that the preferred reaction mechanism of methanol formation would change to the one including the HCOOH intermediate and the reaction prefers to happen at the Pd site, with two formate preadsorbing at the In step-bridge site at the same time. It was found that such changes can be attributed to the reduced barriers of elementary steps in this path introduced by the formate coverage effect. Therefore, it is imperative to carry out a theoretical study for surface reactions by combining DFT calculations and microkinetic analysis and to take the interactions between dominant surface species into account when identifying the mechanism under reaction conditions.

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“…Palladium‐based intermetallic compounds M m Pd n with M = Ga or In (including GaPd, GaPd 2 , Ga 7 Pd 3 and InPd) were proven to be highly selective and stable catalyst materials for the selective hydrogenation of alkynes and the methanol steam reforming reaction . For the industrial heterogeneous catalysis processes it is advantageous to replace precious metals by less expensive alternatives.…”

Section: Introductionmentioning

confidence: 99%

“…reforming reaction. [1][2][3][4][5][6][7][8] For the industrial heterogeneous catalysis processes it is advantageous to replace precious metals by less expensive alternatives. In such an attempt, the intermetallic Al 13 Fe 4 was found to be excellent replacement for palladium in the heterogeneous hydrogenation of alkynes.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Electrical, Magnetic, and Thermal Properties of In₃Ni₂ Intermetallic Catalyst

Krnel

Koželj

Vrtnik

et al. 2020

Zeitschrift anorg allge chemie

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We present the anisotropic electrical and thermal transport coefficients (electrical resistivity, magnetoresistance, thermoelectric power, thermal conductivity), the magnetic properties, the specific heat and the electronic density of states of a monocrystalline In3Ni2 intermetallic compound, representing a precious‐metal‐free (and noble‐metal‐free) intermetallic catalyst for the selective hydrogenation of α,β‐unsaturated aldehydes. The investigated physical parameters were determined along three orthogonal crystal‐symmetry directions of the trigonal structure, the twofold axis, the 3 axis and within the mirror plane. All the investigated tensorial and vectorial quantities show the same anisotropy, with the quantities being isotropic for the twofold direction and in the mirror plane, whereas there is small, though still significant anisotropy to the 3 direction. The In3Ni2 crystal conducts the electricity and heat somewhat less efficiently along the 3 direction than along the twofold direction and in the mirror plane, but the differences are not large, of about 20 %. In3Ni2 is a diamagnetic intermetallic compound, with a presumably simple Fermi surface and electrons as the majority charge carriers.

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Physical properties of the GaPd2 intermetallic catalyst in bulk and nanoparticle morphology

Cited by 5 publications

References 27 publications

Pd₂Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO₂ to Methanol

Pd₂Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO₂ to Methanol

Role of Surface Species Interactions in Identifying the Reaction Mechanism of Methanol Synthesis from CO₂Hydrogenation over Intermetallic PdIn(310) Steps

Anisotropic Electrical, Magnetic, and Thermal Properties of In₃Ni₂ Intermetallic Catalyst

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Physical properties of the GaPd2 intermetallic catalyst in bulk and nanoparticle morphology

Cited by 5 publications

References 27 publications

Pd2Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO2 to Methanol

Pd2Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO2 to Methanol

Role of Surface Species Interactions in Identifying the Reaction Mechanism of Methanol Synthesis from CO2Hydrogenation over Intermetallic PdIn(310) Steps

Anisotropic Electrical, Magnetic, and Thermal Properties of In3Ni2 Intermetallic Catalyst

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Pd₂Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO₂ to Methanol

Pd₂Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO₂ to Methanol

Role of Surface Species Interactions in Identifying the Reaction Mechanism of Methanol Synthesis from CO₂Hydrogenation over Intermetallic PdIn(310) Steps

Anisotropic Electrical, Magnetic, and Thermal Properties of In₃Ni₂ Intermetallic Catalyst