| Records |
| Author |
Schütte, K.; Doddi, A.; Kroll, C.; Meyer, H.; Wiktor, C.; Gemel, C.; Van Tendeloo, G.; Fischer, R.A.; Janiak, C. |
| Title |
Colloidal nickel/gallium nanoalloys obtained from organometallic precursors in conventional organic solvents and in ionic liquids : noble-metal-free alkyne semihydrogenation catalysts |
Type |
A1 Journal article |
Year  |
2014 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
| Volume |
6 |
Issue |
10 |
Pages |
5532-5544 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
Efforts to replace noble-metal catalysts by low-cost alternatives are of constant interest. The organometallic, non-aqueous wet-chemical synthesis of various hitherto unknown nanocrystalline Ni/Ga intermetallic materials and the use of NiGa for the selective semihydrogenation of alkynes to alkenes are reported. Thermal co-hydrogenolysis of the all-hydrocarbon precursors [Ni(COD)(2)] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in high-boiling organic solvents mesitylene and n-decane in molar ratios of 1 : 1, 2 : 3 and 3 : 1 yields the nano-crystalline powder materials of the over-all compositions NiGa, Ni2Ga3 and Ni3Ga, respectively. Microwave induced co-pyrolysis of the same precursors without additional hydrogen in the ionic liquid [BMIm][BF4] (BMIm = 1-butyl-3-methyl-imidazolium) selectively yields the intermetallic phases NiGa and Ni3Ga from the respective 1 : 1 and 3 : 1 molar ratios of the precursors. The obtained materials are characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), IR, powder X-ray diffraction (PXRD) and atomic absorption spectroscopy (AAS). The single-source precursor [Ni(GaCp*)(PMe3)(3)] with a fixed Ni : Ga stoichiometry of 1 : 1 was employed as well. In comparison with the co-hydrogenolytic dual precursor source approach it turned out to be less practical due to inefficient nickel incorporation caused by the parasitic formation of stable [Ni(PMe3)(4)]. The use of ionic liquid [BMIm][BF4] as a non-conventional solvent to control the reaction and stabilize the nanoparticles proved to be particularly advantageous and stable colloids of the nanoalloys NiGa and Ni3Ga were obtained. A phase-selective Ni/Ga colloid synthesis in conventional solvents and in the presence of surfactants such as hexadecylamine (HDA) was not feasible due to the undesired reactivity of HDA with GaCp* leading to inefficient gallium incorporation. Recyclable NiGa nanoparticles selectively semihydrogenate 1-octyne and diphenylacetylene (tolan) to 1-octene and diphenylethylene, respectively, with a yield of about 90% and selectivities of up to 94 and 87%. Ni-NPs yield alkanes with a selectivity of 97 or 78%, respectively, under the same conditions. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
Cambridge |
Editor |
|
| Language |
|
Wos |
000335148800069 |
Publication Date |
2014-03-06 |
| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2040-3364;2040-3372; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
7.367 |
Times cited |
40 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 7.367; 2014 IF: 7.394 |
| Call Number |
UA @ lucian @ c:irua:117251 |
Serial |
390 |
| Permanent link to this record |
| |
|
| |
| Author |
Meyer, H.W.; Bismayer, U.; Adiwidjaja, G.; Zhang, M.; Nistor, L.; Van Tendeloo, G. |
| Title |
Natural titanite and malayite: structural investigations and the 500K anomaly |
Type |
A1 Journal article |
| Year |
1998 |
Publication |
Phase transitions |
Abbreviated Journal |
Phase Transit |
| Volume |
67 |
Issue |
|
Pages |
27-49 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
|
| Address |
|
| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
New York |
Editor |
|
| Language |
|
Wos |
000079806000003 |
Publication Date |
2007-07-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0141-1594;1029-0338; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.06 |
Times cited |
9 |
Open Access |
|
| Notes |
) |
Approved |
Most recent IF: 1.06; 1998 IF: 0.551 |
| Call Number |
UA @ lucian @ c:irua:25683 |
Serial |
2287 |
| Permanent link to this record |
| |
|
| |
| Author |
Groat, L.A.; Kek, S.; Bismayer, U.; Schmidt, C.; Krane, H.G.; Meyer, H.; Nistor, L.; Van Tendeloo, G. |
| Title |
A synchrotron radiation, HRTEM, X-ray powder diffraction, and Raman spectroscopic study of malayaite, CaSnSiO5 |
Type |
A1 Journal article |
| Year |
1996 |
Publication |
The American mineralogist |
Abbreviated Journal |
Am Mineral |
| Volume |
81 |
Issue |
5/6 |
Pages |
595-602 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Synchrotron radiation, high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction, and Raman spectroscopy were used to study the structure and thermal behavior of malayaite, CaSnSiO5. No indications of deviation from A2/a symmetry and no structural transitions were observed between 100 and 870 K. HRTEM revealed that the material is free of domains and antiphase boundaries. However, the lattice constants, cell volume, and Raman-active phonons show a thermal discontinuity near 500 K, which is possibly related to variation of the coordination sphere around the highly anisotropic Ca position. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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| Language |
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Wos |
A1996UP41100006 |
Publication Date |
0000-00-00 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-004x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.964 |
Times cited |
19 |
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ lucian @ c:irua:16862 |
Serial |
3407 |
| Permanent link to this record |
