scholarly journals Synthesis and characterization of Al-and Y-Al-citrates as potential precursors for YAlO3

2006 ◽  
Vol 4 (4) ◽  
pp. 632-645 ◽  
Author(s):  
Nikolina Petrova ◽  
Dimitar Todorovsky ◽  
Daniela Kovacheva ◽  
Maria Milanova
Keyword(s):  
Ethylene Glycol ◽  
Polyester Resin ◽  
Spectral Characteristics ◽  
Complex Method ◽  
X Ray ◽  
Mixed Metal ◽  
Orthorhombic Modification ◽  
Citric Complexes ◽  
Bimetallic System

AbstractAl-and Y-Al-citric complexes have been synthesized in ethylene glycol medium at conditions close to the ones used in polymerized complex method and their composition and spectral characteristics have been studied. Proofs have been found for the formation in the bimetallic system of a mixed-metal Al-Y-complex. Doubly ionized and esterified ligands take place in the Al-complex. All of the ligands forming Y-Al-complex are mono-or doubly esterified. Deprotonation of the alcoholic group takes place in the formation of the mixed-metal complex. Both complexes contain adduct-bonded ethylene glycol. Heating of the bimetallic complex or of the polyester resin formed leads to not phase-homogeneous YAlO3-along with cubic YAlO3, its orthorhombic modification as well as Y4All2O9 are found by X-ray diffractometry.

Mixed Metal Oxide Interfaces: An Experimental and Theoretical Assessment of Secondary Metal Influences in Metal Impregnated Aluminas

1994 ◽  
Vol 368 ◽  
Author(s):  
M. Malaty ◽  
D. Singh ◽  
R. Schaeffer ◽  
S. Jansen ◽  
S. Lawrence
Keyword(s):  
Photoelectron Spectroscopy ◽  
Theoretical Calculations ◽  
Mixed Metal Oxide ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Mixed Metal ◽  
Metal Interactions ◽  
Metal Metal ◽  
Bimetallic System

ABSTRACTStudies of the mixed-metal interface in metal impregnated alumina have indicated the possibility of much metal-metal and metal-substrate interaction. Studies were carried out on NiCu/Al2O3 system which was evaluated to develop a better understanding of the forces that drive modification of the catalytic selectivity of Ni in the presence of Cu. Electron Paramagnetic Resonance (EPR), Powder X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD) and theoretical calculations were carried out on this bimetallic system, using Ni,Ag/Al2O3 as a reference as Ni shows negligible electron perturbation on co-adsorbance with Ag onto alumina. XRD results indicate that gross modification of the electronic fields of Ni and Cu are due to direct coupling and intercalation into the alumina matrix. As a result of this phenomena, these materials may form a good base for the development of novel ceramics based on mixed-metal interactions where the intermetallic perturbations are driven by the substrate effects.

Mixed-metal gold clusters. Synthesis and x-ray structural characterization of [Au5Re(H)4(PPh3)7](PF6)2 and [Au3Rh(H)(CO)(PPh3)5](PF6)

1986 ◽  
Vol 25 (1) ◽  
pp. 5-7 ◽  
Author(s):  
Paul D. Boyle ◽  
Brian J. Johnson ◽  
Angela Buehler ◽  
Louis H. Pignolet
Keyword(s):  
Structural Characterization ◽  
Gold Clusters ◽  
X Ray ◽  
Mixed Metal

scholarly journals Preparation and characterization of high-dispersed pt/c nano-electrocatalysts for fuel cell applications.

2016 ◽  
Vol 54 (4) ◽  
pp. 472
Author(s):  
Hoang Anh Huy ◽  
Tran Van Man ◽  
Huynh Thien Tai ◽  
Ho Thi Thanh Van
Keyword(s):  
Fuel Cell ◽  
Ethylene Glycol ◽  
Pt Nanoparticles ◽  
Carbon Support ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Synthesis Conditions ◽  
Size Dispersion

Synthesis conditions are keys to controlling size and dispersion of Platinum (Pt) nanoparticle structures that is one of the most important goals in improving the electrochemical activity and durability of electrocatalyst as Pt nanoparticles catalyst for fuel cells. In this study, we introduce a simple method to address the effects of the temperature, pH and ethylene glycol enhancers (EG) on the morphology and size distribution of Pt nanoparticles catalyst in electrocatalyst fabrication process Pt nanoparticles on carbon support (Pt NPs/C). By using a facile method, we synthesized Pt NPs/C catalyst with and without using EG at room temperature and 60°C in pH = 6.5 and 11 solutions. The morphology, size, dispersion and activity of Pt nanoparticles catalyst on carbon support were characterized by using X-ray diffraction (XRD), Transmissionelectron microscopy (TEM) and Cyclic Voltammetry (CV). We found that the size, morphology and dispersion of Pt nanoparticles on carbon were strongly affected by adjusting the temperature, pH and the presence of ethylene glycol that could enhance catalytic activity of Platinum for fuel cell applications.

Re-evaluation of the X-Ray Crystal Structure of [Ta4F20] and the Synthesis and Characterization of a Series of Mixed-Metal Pentafluorides of Niobium and Tantalum.

ChemInform ◽  
2006 ◽  
Vol 37 (13) ◽  
Author(s):  
Stuart A. Brewer ◽  
Alan K. Brisdon ◽  
John Fawcett ◽  
Peter J. Holliman ◽  
John H. Holloway ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Mixed Metal

Preparation and Characterization of Perovskite Pb(Mg1/3Nb2/3)O3-PbTiO3 by a Modified Polymerized Complex Process

2008 ◽  
Vol 368-372 ◽  
pp. 30-32 ◽  
Author(s):  
Jin Chen ◽  
Hui Qing Fan ◽  
Shao Jun Qiu
Keyword(s):  
Lead Acetate ◽  
Perovskite Phase ◽  
Pyrochlore Phase ◽  
Phase Evolution ◽  
Complex Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complex Process ◽  
Scanning Electron

Relaxor-based ferroelectrics, 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (PMN-PT) with a pyrochlore-free phase, was prepared by a modified polymerized complex process. The reactive columbite (MgNb2O6) phase was synthesized by the polymerized complex method at 1050oC for 4 h with 3wt% excess MgO. Lead acetate and tetrebutyl titanate were used to synthesize pyrochlore-free PMN-PT powder via the columbite route, from 800oC to 900oC, in air for 4 h. X-ray diffraction and scanning electron microscopy were used to detect the perovskite phase evolution and the presence of the pyrochlore phase in PMN-PT. The formation of perovskite PMN-PT is a function of the time and temperature conditions of the precursor calcinations, and an optimum condition for the thermal decomposition of the precursor was determined to avoid the formation of the pyrochlore phase.

Re-evaluation of the X-ray Crystal Structure of [Ta4F20] and the Synthesis and Characterization of a Series of Mixed-Metal Pentafluorides of Niobium and Tantalum

2006 ◽  
Vol 632 (2) ◽  
pp. 325-329 ◽  
Author(s):  
Stuart A. Brewer ◽  
Alan K. Brisdon ◽  
John Fawcett ◽  
Peter J. Holliman ◽  
John H. Holloway ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Mixed Metal
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