Initial nucleation process in the synthesis of Platinum Nanoparticle from chloroplatinic acid

STEM coupled with the optical system was used for the investigation of the early oxidation on the surface of Cr. Cr thin films (30 – 1000Å) were prepared by evaporation onto the polished or air-cleaved NaCl substrates at room temperature and 45°C in a vacuum of 10−6 Torr with an evaporation speed 0.3Å/sec. Rather thick specimens (200 – 1000Å) with various preferred orientations were used for the investigation of the oxidation at moderately high temperature (600 − 1100°C). Selected area diffraction patterns in these specimens are usually very much complicated by the existence of the different kinds of oxides and their multiple twinning. The determination of the epitaxial orientation relationship of the oxides formed on the Cr surface was made possible by intensive use of the optical system and microdiffraction techniques. Prior to the formation of the known rhombohedral Cr2O3, a thin spinel oxide, probably analogous to γ -Al203 or γ -Fe203, was formed. Fig. 1a shows the distinct epitaxial growth of the spinel (001) as well as the rhombohedral (125) on the well-oriented Cr(001) surface. In the case of the Cr specimen with the (001) preferred orientation (Fig. 1b), the rings explainable by spinel structure appeared as well as the well defined epitaxial spots of the spinel (001). The microdif fraction from 20A areas (Fig. 2a) clearly shows the same pattern as Fig. Ia with the weaker oxide spots among the more intense Cr spots, indicating that the thickness of the oxide is much less than that of Cr. The rhombohedral Cr2O3 was nucleated preferably at the Cr(011) sites provided by the polycrystalline nature of the present specimens with the relation Cr2O3 (001)//Cr(011), and by further oxidation it grew into full coverage of the rest of the Cr surface with the orientation determined by the initial nucleation.

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STUDY OF NUCLEATION PROCESS IN (SiO2, Al2O3, Li2O) GLASSES, BY X-RAY ABSORPTION SPECTROSCOPY AND TRANSMISSION ELECTRON MICROSCOPY

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1985876 ◽

1985 ◽

Vol 46 (C8) ◽

pp. C8-491-C8-494 ◽

Cited By ~ 1

Author(s):

A. Ramos ◽

M. Gandais ◽

J. Petiau

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Absorption Spectroscopy ◽

Nucleation Process ◽

X Ray ◽

Transmission Electron ◽

X Ray Absorption

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Effects of Initial Nucleation Condition at the Start Block on the Grain Size and Growth Direction in Directionally Solidified CM247LC Superalloy

Korean Journal of Metals and Materials ◽

10.3365/kjmm.2011.49.1.058 ◽

2011 ◽

Vol 49 (01) ◽

pp. 58-63

Author(s):

Hye-Young Yoon ◽

Je-Hyun Lee ◽

Hyeong-Min Jung ◽

Seong-Moon Seo ◽

Chang-Young Jo ◽

...

Keyword(s):

Grain Size ◽

Growth Direction ◽

Directionally Solidified ◽

Initial Nucleation

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Mechanistic Study on Facet-Dependent Deposition of Metal Nanoparticles on Decahedral-Shaped Anatase Titania Photocatalyst Particles

Catalysts ◽

10.3390/catal8110542 ◽

2018 ◽

Vol 8 (11) ◽

pp. 542 ◽

Cited By ~ 4

Author(s):

Kenta Kobayashi ◽

Mai Takashima ◽

Mai Takase ◽

Bunsho Ohtani

Keyword(s):

Mechanistic Study ◽

Phase Reaction ◽

Surface Charges ◽

Platinum Nanoparticle ◽

Nanoparticle Deposition ◽

Selective Reaction ◽

Anatase Titania ◽

Deposition Density ◽

Titania Photocatalyst ◽

Source Materials

Facet-selective gold or platinum-nanoparticle deposition on decahedral-shaped anatase titania particles (DAPs) exposing {001} and {101} facets via photodeposition (PD) from metal-complex sources was reexamined using DAPs prepared with gas-phase reaction of titanium (IV) chloride and oxygen by quantitatively evaluating the area deposition density on {001} and {101} and comparing with the results of deposition from colloidal metal particles in the dark (CDD) or under photoirradiation (CDL). The observed facet selectivity, more or less {101} preferable, depended mainly on pH of the reaction suspensions and was almost non-selective at low pH regardless of the deposition method, PD or CDL, and the metal-source materials. Based on the results, the present authors propose that facet selectivity is attributable to surface charges (zeta potential) depending on the kind of facets, {001} and {101}, and pH of the reaction mixture and that this concept can explain the observed facet selectivity and possibly the reported facet selectivity without taking into account facet-selective reaction of photoexcited electrons and positive holes on {101} and {001} facets, respectively.

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3D Microprinting of Iron Platinum Nanoparticle‐Based Magnetic Mobile Microrobots

Advanced Intelligent Systems ◽

10.1002/aisy.202170012 ◽

2021 ◽

Vol 3 (1) ◽

pp. 2170012

Author(s):

Joshua Giltinan ◽

Varun Sridhar ◽

Ugur Bozuyuk ◽

Devin Sheehan ◽

Metin Sitti

Keyword(s):

Platinum Nanoparticle ◽

Iron Platinum

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Study on the continuous precipitation of U(IV) oxalate in a vortex precipitator

Radiochimica Acta ◽

10.1515/ract-2020-0069 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Chuanbo Li ◽

Yongzhi Ning ◽

Taihong Yan ◽

Weifang Zheng

Keyword(s):

Oxalic Acid ◽

Residence Time ◽

Nitrate Solution ◽

The Other ◽

Nucleation Process ◽

Average Residence Time ◽

Continuous Precipitation ◽

Vortex Zone ◽

Forced Vortex ◽

Particles Size Distribution

Abstract The effects of feeding location, stirring speed and apparent average residence time on oxalate crystals size and distribution, tackiness of the product on the walls of reactor and stirring paddle were investigated in a vortex continuous precipitator at 45 °C. The results showed agglomeration happened during nucleation and crystals growth of U(IV) oxalate. Both local supersaturations and agglomeration maked the particles size distribution of U(IV) oxalate from 10–100 µm and the average sizes 35–45 µm. On the other hand, when the nucleation process were controlled to happen in the forced vortex zone, two feeding locations: (a) both oxalic acid and U(IV) nitrate solution into the forced vortex zone, (b) oxalic acid into the free vortex and U(IV) nitrate solution into the forced vortex, tackiness of the crystals on the wall of the precipitator could be effectively avoided.

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