scholarly journals Ultrafine metal-polymer catalysts based on polyconjugated systems for Fisher–Tropsch synthesis

2020 ◽  
Vol 92 (6) ◽  
pp. 977-984
Author(s):  
Mayya V. Kulikova ◽  
Albert B. Kulikov ◽  
Alexey E. Kuz’min ◽  
Anton L. Maximov
Keyword(s):  
Tropsch Synthesis ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
Force Microscopy ◽  
Composite Catalysts ◽  
Fe Catalyst ◽  
Atomic Force ◽  
And Function ◽  
Metal Polymer

AbstractFor previously studied Fischer–Tropsch nanosized Fe catalyst slurries, polymer compounds with or without polyconjugating structures are used as precursors to form the catalyst nanomatrix in situ, and several catalytic experiments and X-ray diffraction and atomic force microscopy measurements are performed. The important and different roles of the paraffin molecules in the slurry medium in the formation and function of composite catalysts with the two types of aforementioned polymer matrices are revealed. In the case of the polyconjugated polymers, the alkanes in the medium are “weakly” coordinated with the metal-polymer composites, which does not affect the effectiveness of the polyconjugated polymers. Otherwise, alkane molecules form a “tight” surface layer around the composite particles, which create transport complications for the reagents and products of Fischer-Tropsch synthesis and, in some cases, can change the course of the in situ catalyst formation.

Large Area Supersonic Jet Epitaxy of AlN, GaN, and SiC on Silicon

1996 ◽  
Vol 449 ◽  
Author(s):  
L.J. Lauhon ◽  
S. A. Ustin ◽  
W. Ho
Keyword(s):  
Supersonic Jet ◽  
X Ray Diffraction ◽  
Large Area ◽  
Free Jets ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Supersonic Jet Epitaxy ◽  
Carrier Gases

ABSTRACTAlN, GaN, and SiC thin films were grown on 100 mm diameter Si(111) and Si(100) substrates using Supersonic Jet Epitaxy (SJE). Precursor gases were seeded in lighter mass carrier gases and free jets were formed using novel slit-jet apertures. The jet design, combined with substrate rotation, allowed for a uniform flux distribution over a large area of a 100 mm wafer at growth pressures of 1–20 mTorr. Triethylaluminum, triethylgailium, and ammonia were used for nitride growth, while disilane, acetylene, and methylsilane were used for SiC growth. The films were characterized by in situ optical reflectivity, x-ray diffraction (XRD), atomic force microscopy (AFM), and spectroscopic ellipsometry (SE).

(G03 Best Paper Award Winner) Analysis of Sn Behavior During Ni/GeSn Solid-State Reaction by Correlated X-ray Diffraction, Atomic Force Microscopy, and Ex-situ/In-situ Transmission Electron Microscopy

2020 ◽  
Vol MA2020-02 (24) ◽  
pp. 1750-1750
Author(s):  
Andrea Quintero Colmenares ◽  
Patrice Gergaud ◽  
Jean-Michel Hartmann ◽  
Vincent Delaye ◽  
Nicolas Bernier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ex Situ ◽  
Paper Award ◽  
X Ray Diffraction ◽  
Award Winner ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Growth of (0001) ZnO Thin Films on Sapphire

1996 ◽  
Vol 449 ◽  
Author(s):  
A. J. Drehman ◽  
P. W. Yip
Keyword(s):  
Surface Roughness ◽  
Buffer Layers ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force

ABSTRACTUsing reactive rf sputtering, we have grown (0001) oriented ZnO films in situ on heated c-axis sapphire substrates, that are promising, particularly in terms of surface roughness, as buffer layers for the subsequent epitaxial growth of III-V nitride films. We compare the effects of on-axis and off-axis sputter geometries on the film epitaxy and smoothness. We also examined the effect of substrate temperature on the growth and smoothness and quality of the film. X-ray diffraction was used to verify the hexagonal ZnO phase, its c-axis orientation and, qualitatively, the degree of its epitaxy. Atomic Force Microscopy (AFM) was used to determine the ZnO growth morphology and roughness. Our best films, obtained by off-axis sputter deposition, have a surface roughness of less than 1 nm.

Surface Structural Characterization and Mechanical Testing by Nanoindentation Measurements of Hybrid Polymer/clay Nanostructured Multilayer Films

2002 ◽  
Vol 17 (7) ◽  
pp. 1622-1633 ◽  
Author(s):  
Xiaowu Fan ◽  
Mi-Kyoung Park ◽  
Chuanjun Xia ◽  
Rigoberto Advincula
Keyword(s):  
Thin Films ◽  
Quartz Crystal ◽  
Ex Situ ◽  
Multilayer Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Diallyldimethylammonium Chloride

Nanostructured montmorillonite/poly(diallyldimethylammonium chloride) multilayer thin films were fabricated up to 100 layers thick by stepwise alternating polyelectrolyte and clay deposition from solution. The structure and morphology of the films were characterized by x-ray diffraction, ellipsometry, atomic force microscopy, and quartz crystal microbalance ex situ and in situ measurements. The mechanical properties were tested by nanoindentation. The hardness of the multilayer thin film was 0.46 GPa. The thin film's modulus was correlated to its ordering and anisotropic structure. Both hardness and modulus of this composite film were higher than those of several other types of polymer thin films.

Drastic Change in the Gan Film Quality by In-Situ Controlling Surface Reconstructions In Gsmbe

1997 ◽  
Vol 482 ◽  
Author(s):  
X. Q. Shen ◽  
S. Tanaka ◽  
S. Iwai ◽  
Y. Aoyagi
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Gas Source ◽  
Atomic Force ◽  
Surface Reconstructions ◽  
Gan Film

AbstractGaN growth was performed on 6H-SiC (0001) substrates by gas-source molecular beam epitaxy (GSMBE), using ammonia (NH3) as a nitrogen source. Two kinds of reflection high-energy electron diffraction (RHEED) patterns, named (1×1) and (2×2), were observed during the GaN growth depending on the growth conditions. By careful RHEED study, it was verified that the (1×1) pattern was corresponded to a H2-related nitrogen-rich surface, while (2×2) pattern was resulted from a Ga-rich surface. By x-ray diffraction (XRD), photoluminescence (PL) and atomic force microscopy (AFM) characterizations, it was found that the GaN quality changed drastically grown under different RHEED patterns. GaN film grown under the (1×1) RHEED pattern showed much better qualities than that grown under the (2×2) one.

Dielectric and Electromechanical Behaviour of Relaxor [(1−x)Pb(Mg1/3Nb2/3)O3 -xPbTiO3] Thin Films

2001 ◽  
Vol 688 ◽  
Author(s):  
N.J. Donnelly ◽  
G. Catalan ◽  
C. Morros ◽  
R.M. Bowman ◽  
J.M. Gregg
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Plane Strain ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Bulk Ceramic ◽  
Atomic Force ◽  
Out Of Plane ◽  
Order Of Magnitude

AbstractThin film capacitor structures of Au / (1−x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3 /(La1/2Sr1/2)CoO3 were fabricated by pulsed laser deposition on single crystal {001} MgO substrates. Films were found to be perovskite dominated and highly {001} oriented. Dielectrically, films displayed relaxorlike features, though maximum permittivity was low compared to single crystal or bulk ceramic (∼1400 at peak @1kHz, for x=0.07, 0.1 & 0.2). A field induced piezoelectric coefficient d33 was measured by piezoresponse atomic force microscopy for specific compositions x =0, × =0.07, and x =0.1 and found to be disappointingly low - indicating poor electric field induced strain. Despite this macroscopic electrostrictive coefficients Q33 were found to be (3.6 ± 0.6) ×10−2C−2m4, (2.6 ± 0.2) ×10−2C−2m4, and (0.9 ± 0.3) ×10−2C−2m4 respectively. Crystallographic electrostrictive coefficients were determined by in-situ x-ray diffraction and found to be (4.9 ± 0.2) ×10−2C−2m4 for PMN-(0.07)PT and (1.9 ± 0.1) ×10−2C−2m4 for PMN-(0.1)PT. Considering that all these Q33 values are of the same order of magnitude as found in single crystal experiments (2.5 – 3.8 ×10−2C−2m4), it is suggested that low out-of-plane strain is entirely a result of reduced polarisability rather than reduced electrostrictive coefficients in thin films relative to bulk ceramic or single crystal. An estimate was also made of the Q13 electrostrictive coefficient for PMN and PMN-(0.07)PT by measuring permittivity as a function of applied in-plane strain. The values obtained were -1.31 ×10−2C−2m4 and -0.46 ×10−2C−2m4 respectively.

Preparation of (111)-Oriented Pt Electrode Films with Quasi-Monocrystal Properties on MgO/TiN Buffered Si(100) by PLD

2007 ◽  
Vol 280-283 ◽  
pp. 823-826 ◽  
Author(s):  
Tong Lai Chen ◽  
Xiao Min Li
Keyword(s):  
High Energy ◽  
Layer Growth ◽  
Atomic Scale ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Pt Electrode ◽  
Force Microscopy ◽  
Atomic Force

Atomic-scale smooth Pt electrode films have been deposited on MgO/TiN buffered Si (100) by the pulsed laser deposition (PLD) technique. The whole growth process of the multilayer films was monitored by using in-situ reflection high energy electron diffraction (RHEED) apparatus. The Pt/MgO/TiN/Si(100) stacked structure was also characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The HREED observations show that the growth mode of the Pt electrode film is 2D layer-by-layer growth. It is found that the (111)-oriented Pt electrode film has a crystallinity comparable to that of monocrystals. The achievement of the quasi-single-crystal Pt electrode film with an atomic-scale smooth surface is ascribed to the improved crystalline quality of the MgO film.

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