Simple vapor-solid synthesis of Zn-based intermetallic compounds

Ivarsson, Dennis C. A.; Burkhardt, Ulrich; Richter, Klaus W.; Kriegel, René; Rößner, Leonard; Neumann, Matthias; Armbrüster, Marc

doi:10.1016/j.jallcom.2018.01.385

Cited by 5 publications

(12 citation statements)

References 43 publications

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“…For the preparation of Zn 100− x Pd x ( x= 48.1–58.0) samples, Pd foil (ChemPur, 99.9 %, thickness: 0.25 mm, used in one piece) and zinc granules (ChemPur, 99.999 %, diameter: 1–5 mm) were used. To obtain dense samples, the recently developed solid–vapor synthesis method was applied . Direct contact of Zn and Pd was avoided by means of a neck.…”

Section: Methodsmentioning

confidence: 99%

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Formic Acid Decomposition over ZnPd—Implications for Methanol Steam Reforming

2018

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Single‐phase ZnPd with different elemental composition as well as ZnO‐supported ZnPd nanoparticles were prepared and tested concerning their catalytic properties in the formic acid decomposition with the aim to investigate a possible formate pathway in the steam reforming of methanol (MSR). Pd‐rich ZnPd showed higher catalytic activity than ZnPd with lower Pd content. All samples showed high and stable CO2 selectivity. The stability of the materials was investigated both ex situ by powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy after formic acid decomposition as well as by in situ X‐ray photoelectron spectroscopy (in situ XPS) and operando differential thermal analysis–thermogravimetry (DTA/TG). Samples with higher Pd content exhibited higher stability against oxidation, corroborating earlier observations under MSR conditions. The supported ZnPd/ZnO material and Zn‐rich bulk ZnPd samples showed a strong modification after reaction, which is attributed to zinc formate formation during formic acid decomposition. Kinetic data give strong indications to exclude dehydrogenation of a formate intermediate as rate‐limiting step in MSR.

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Section: Methodsmentioning

confidence: 99%

“…To obtain dense samples, the recently developed solid-vapor synthesis method was applied. [26] Direct contact of Zn and Pd was avoided by means of an eck. The tube was placed in af urnace and the temperature was increased with 60 8Ch À1 to 500 8C.…”

Section: Methodsmentioning

confidence: 99%

Formic Acid Decomposition over ZnPd—Implications for Methanol Steam Reforming

2018

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“…This could be due to differences in zinc segregation caused by the different occupation of crystallographic positions depending on the elemental composition, i. e. mixed occupancy to realize the different compositions. [27] The fluctuations in the potential profile without conscious external influence show the . Calculated approximation of high temperature activity values from the CuÀ Zn system [40,48,49] to ambient temperature and comparison with experimental values determined at ambient temperature.…”

Section: Emf Measurements On Intermetallic Znpd Electrodesmentioning

confidence: 98%

“…For the preparation of intermetallic electrodes of Cu 5 Zn 8 /ZnPd/ZnPt Cu-foils (Alfa Aesar, 99.999 %, thickness: 0.1 mm)/Pd-foils (ChemPur, 99.9 %, thickness: 0.25 mm)/Pt-foils (ChemPur, 99.99 %, thickness: 0.1 mm), each with a width of roughly 1 cm and a length of up to 2.5 cm, and zinc granules (Alfa Aesar, 99.9999 %, diameter: 1-6 mm) were used to obtain samples in the form of foils. [27] The weighted reactants were evacuated and sealed in quartz glass ampoules avoiding direct contact of the zinc granules and the corresponding foil by means of a neck. The evacuated tubes were placed upright in a furnace and heated to 450°C with 60 Kh À 1 , held for one day, before heating to 720°C (for the preparation of Cu 5 Zn 8 -foils), or 900°C (for the preparation of ZnPd-and ZnPt-foils) with 60 Kh À 1 followed by 10 to 90 days of annealing.…”

Section: Experimental Section Synthesismentioning

confidence: 99%

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Corrosion‐Free EMF Measurements of Zinc‐Based Intermetallic Compounds at Ambient Temperature

Kriegel

Armbrüster

2020

ChemPhysChem

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Material development requires in many cases information about the necessary stability of the materials against oxidation, which is encoded in the chemical activity of the constituting elements. Determination of the chemical activity is tedious, especially for metallic materials at or close to ambient temperature. To determine the chemical activity of Zn at ambient temperature, electromotive force (EMF) measurements on the intermetallic compounds ZnPd, ZnPt and Cu 5 Zn 8 within their respective homogeneity range were conducted. The single-phase nature of the samples was confirmed by powder X-ray diffraction, light microscopy as well as SEM/EDX analysis. To exclude oxidation, and therefore faulty determination of the electrochemical potentials, a method was developed to conduct the electro-chemical measurements under non-corrosive conditions in inert atmosphere. Corrosion by the electrolyte was avoided using anhydrous dimethylformamide as aprotic solvent. From the EMF the respective intrinsic activities of zinc in the corresponding intermetallic compounds was determined. Measurements on Cu 5 Zn 8 and comparison to available data in literature verified the developed method allowing to retrieve thermodynamic data of ZnPd and ZnPt for the first time at ambient temperature. The herein developed and easy-to-use methodology is applicable to a wide range of metallic material by choosing appropriate compositions of the electrolyte and has the potential to boost material development.[a] Dr.

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Facile Thermodynamically Controlled Synthesis of Intermetallic Zn_1–xPd_x/Al₂O₃ and Its Methanol Steam Reforming Properties

Wibner,

Kriegel,

Garstenauer

et al. 2024

J. Phys. Chem. C

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High-performance heterogeneous catalytic materials are most frequently based on supported nanoparticles to gain high dispersion and thus high atom efficiency. The materials are usually obtained by kinetically controlled synthesis, making repetitive synthesis of materials with identical properties a challenge. While this holds for monometallic-supported particles, the situation is even more severe with binary-supported substitutional alloys or intermetallic compounds, where control of the homogeneous elemental composition of the nanoparticles comes close to an art. We propose an innovative synthesis route to Zn1–x Pd x /Al2O3, controlling thermodynamically the composition and homogeneity of the Zn1–x Pd x particlesan intermetallic compound having a significant homogeneity range and catalyzing numerous reactions. The thermodynamic control is achieved by the direct reaction of supported palladium nanoparticles with gaseous zinc. The resulting Zn1–x Pd x /Al2O3 samples are characterized in detail concerning their particle composition, particle size distribution, and crystal structure of the intermetallic nanoparticles, using XRD, TEM, XPS, ICP-MS and ICP-OES. Subsequent testing in methanol steam reforming reveals excellent catalytic properties.

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Simple vapor-solid synthesis of Zn-based intermetallic compounds

Cited by 5 publications

References 43 publications

Formic Acid Decomposition over ZnPd—Implications for Methanol Steam Reforming

Formic Acid Decomposition over ZnPd—Implications for Methanol Steam Reforming

Corrosion‐Free EMF Measurements of Zinc‐Based Intermetallic Compounds at Ambient Temperature

Facile Thermodynamically Controlled Synthesis of Intermetallic Zn_1–xPd_x/Al₂O₃ and Its Methanol Steam Reforming Properties

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Simple vapor-solid synthesis of Zn-based intermetallic compounds

Cited by 5 publications

References 43 publications

Formic Acid Decomposition over ZnPd—Implications for Methanol Steam Reforming

Formic Acid Decomposition over ZnPd—Implications for Methanol Steam Reforming

Corrosion‐Free EMF Measurements of Zinc‐Based Intermetallic Compounds at Ambient Temperature

Facile Thermodynamically Controlled Synthesis of Intermetallic Zn1–xPdx/Al2O3 and Its Methanol Steam Reforming Properties

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Facile Thermodynamically Controlled Synthesis of Intermetallic Zn_1–xPd_x/Al₂O₃ and Its Methanol Steam Reforming Properties