Metals and alloys of the platinum group

Raub, Ernst

doi:10.1016/0022-5088(59)90014-1

Cited by 159 publications

(46 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fcc lattice parameter, as obtained from XRD, together with the average particle sizes, as determined by TEM, is listed in Table 1. The lattice parameters vary linearly with the composition, in agreement with bulk Pd-Rh alloys (Raub, 1959). This trend is typical for substitutional alloys and proves the formation of Pd-Rh nanoalloys in our synthetic conditions.…”

Section: Results Crystalline Structure and Nanostructuresupporting

confidence: 83%

“…Typical TEM images and histograms of particle size for all Pd-Rh nanoalloys are shown in Figure S1 in Supplementary Material. Although the diffraction peaks are very board, XRD investigations prove that these nanoparticles adopt a fcc crystal structure Fm m 3 ( ) typical for Pd-Rh bulk alloys (Raub, 1959). The fcc lattice parameter, as obtained from XRD, together with the average particle sizes, as determined by TEM, is listed in Table 1.…”

Section: Results Crystalline Structure and Nanostructurementioning

confidence: 97%

“…Theoretical phases and amplitudes were computed with FEFF8 on the basis of Pd and Rh metal fcc structures (Ankudinov et al, 1998(Ankudinov et al, , 2003. Due to the close proximity of Rh and Pd in the periodic table and their similar atomic radius, it was not possible to distinguish Pd and Rh first neighbors Raub (1959) and Noh et al (1993).…”

Section: X-ray Absorption Spectroscopymentioning

confidence: 99%

See 2 more Smart Citations

Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

et al. 2016

View full text Add to dashboard Cite

Recent advances on synthesis, characterization, and hydrogen absorption properties of ultrasmall metal nanoparticles (defined here as objects with average size ≤3 nm) are briefly reviewed in the first part of this work. The experimental challenges encountered in performing accurate measurements of hydrogen absorption in Mg-and noble metal-based ultrasmall nanoparticles are addressed. The second part of this work reports original results obtained for ultrasmall bulk-immiscible Pd-Rh nanoparticles. Carbonsupported Pd-Rh nanoalloys in the whole binary chemical composition range have been successfully prepared by liquid impregnation method followed by reduction at 300°C. EXAFS investigations suggested that the local structure of these nanoalloys is partially segregated into Rh-rich core and Pd-rich surface coexisting within the same nanoparticles. Downsizing to ultrasmall dimensions completely suppresses the hydride formation in Pd-rich nanoalloys at ambient conditions, contrary to bulk and larger nanosized (5-6 nm) counterparts. The ultrasmall Pd90Rh10 nanoalloy can absorb hydrogen-forming solid solutions under these conditions, as suggested by in situ X-ray diffraction (XRD). Apart from this composition, common laboratory techniques, such as in situ XRD, DSC, and PCI, failed to clarify the hydrogen interaction mechanism: either adsorption on developed surfaces or both adsorption and absorption with formation of solid solutions. Concluding insights were brought by in situ EXAFS experiments at synchrotron: ultrasmall Pd75Rh25 and Pd50Rh50 nanoalloys absorb hydrogen-forming solid solutions at ambient conditions. Moreover, the hydrogen solubility in these solid solutions is higher with increasing Pd content, and this trend can be understood in terms of hydrogen preferential occupation in the Pd-rich regions, as suggested by in situ EXAFS. The Rh-rich nanoalloys (Pd25Rh75 and Pd10Rh90) only adsorb hydrogen on the developed surface of ultrasmall nanoparticles. In summary, in situ characterization techniques carried out at large-scale facilities are unique and powerful tools for in-depth investigation of hydrogen interaction with ultrasmall nanoparticles at local level.

show abstract

Section: Results Crystalline Structure and Nanostructuresupporting

confidence: 83%

Section: Results Crystalline Structure and Nanostructurementioning

confidence: 97%

Section: X-ray Absorption Spectroscopymentioning

confidence: 99%

See 1 more Smart Citation

Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Cell data versus composition for (Pt,Ir) have been studied by Raub [6] and by Tripathi and Chandrasekharaiah [7] who report data for 13 compositions each. Tripathi reports significant deviations from Vegard's law, with the worst deviations under 50% Ir, but Raub's data points in this range follow rather nicely Vegard's straight line.…”

Section: (Ptir)mentioning

confidence: 99%

Small step graphs of cell data versus composition for ccp solid-solution binary alloys: Application to the (Pt,Ir), (Pt,Re) and (Pt,Ru) systems

Page

Bock

Rodgers³

2006

Journal of Alloys and Compounds

View full text Add to dashboard Cite

“…Earlier, 4 we have studied in detail thermolysis of the [Pd(NH 3 6 ] salt under quenching conditions. In these experiments, we measured X ray diffraction pat terns of samples, which were quenched from the equilib rium state, at room temperature and also in situ in a high temperature X ray chamber.…”

mentioning

confidence: 99%

High-temperature X-ray diffraction study of thermolysis of the double complex salt [Rh(NH3)5Cl][PtCl4]

2006

View full text Add to dashboard Cite

ul. Kutateladze, 630128 Novosibirsk, Russian Federation. The formation process of a nanosize powder of the equilibrium solid solution Pt 0.50 Rh 0.50 by thermolysis of the double complex salt [Rh(NH 3 ) 5 Cl][PtCl 4 ] under hydrogen or helium and in vacuo was studied in situ by X ray diffraction and synchrotron radiation. The reduction temperature of the metals in the cationic and anionic moieties of the starting complex is the main factor responsible for the mechanism of solid solution formation.Heteroatomic metallic phases and composites with a crystallite size smaller than 100 nm can be prepared by crystallization of amorphous alloys and mechanochemi cal alloying, 1 as well as by decomposition of precursors containing atoms of two or more metals. Double complex salts, which consist of complex cations and anions con taining various transition metals as the central atoms, serve as the starting compounds for the preparation of bimetallic powders. Nanosize powders with different phase compositions, including metastable oversaturated solid solutions, can be prepared by varying the coordination environment, the temperature parameters of the decom position process of complex salts, and the gas medium. 2Investigation of the mechanism of thermolysis of double complex salts is of considerable practical interest, in particular, for the development of procedures for the preparation of supported catalysts. 3 Compared to con ventional methods for the preparation of bimetallic mate rials, the latter method allows one to prepare metallic phases at substantially lower temperatures. Due to the fact that precursors contain metal atoms in a stoichiomet ric ratio and these atoms are already "mixed" at molecular level, the problem of preparation of homogeneous mate rials of strictly specified compositions, which are located in phase diagrams in the immiscibility region, has been successfully solved in some cases.Earlier, 4 we have studied in detail thermolysis of the [Pd(NH 3 ) 4 ][IrCl 6 ] salt under quenching conditions. In these experiments, we measured X ray diffraction pat terns of samples, which were quenched from the equilib rium state, at room temperature and also in situ in a high temperature X ray chamber. The formation steps of the

show abstract

Metals and alloys of the platinum group

Cited by 159 publications

References 8 publications

Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

Small step graphs of cell data versus composition for ccp solid-solution binary alloys: Application to the (Pt,Ir), (Pt,Re) and (Pt,Ru) systems

High-temperature X-ray diffraction study of thermolysis of the double complex salt [Rh(NH3)5Cl][PtCl4]

Contact Info

Product

Resources

About