Group 13 metal doped Cu/ZnO catalysts from phase pure precursors via an isomorphous substitution route: mechanistic insights into promotional effects for syngas hydrogenation to methanol

2020 ◽  
Vol 10 (21) ◽  
pp. 7386-7398
Author(s):  
Nilesh Narkhede ◽  
Huayan Zheng ◽  
Huacheng Zhang ◽  
Guoqiang Zhang ◽  
Zhong Li
Keyword(s):  
Methanol Synthesis ◽  
Single Phase ◽  
Isomorphous Substitution ◽  
Group 13 ◽  
Phase Pure ◽  
Efficient Route ◽  
Metal Doped ◽  
Maximum Utilization

An efficient route for promoter incorporation into a single phase zM precursor has been demonstrated, which enables the maximum utilization of the promotional action for methanol synthesis.

Substrate templated synthesis of single-phase and uniform Zr-porphyrin-based metal–organic frameworks

2020 ◽  
Vol 7 (1) ◽  
pp. 221-231
Author(s):  
Seong Won Hong ◽  
Ju Won Paik ◽  
Dongju Seo ◽  
Jae-Min Oh ◽  
Young Kyu Jeong ◽  
...  
Keyword(s):  
Chemical Bath Deposition ◽  
Single Phase ◽  
Metal Organic Frameworks ◽  
Templated Synthesis ◽  
Pore Structures ◽  
Phase Pure ◽  
Metal Organic ◽  
Cbd Method

We successfully demonstrate that the chemical bath deposition (CBD) method is a versatile method for synthesizing phase-pure and uniform MOFs by controlling their nucleation stages and pore structures.

scholarly journals Characterisation of K-doped Bi4V2O11 by combined XRD and EPMA: A cautionary tale

1997 ◽  
Vol 12 (4) ◽  
pp. 245-247 ◽  
Author(s):  
C. K. Lee ◽  
A. M. Coats ◽  
A. R. West
Keyword(s):  
Powder Diffraction ◽  
Electron Probe ◽  
Solid Electrolytes ◽  
Single Phase ◽  
Variable Composition ◽  
Cautionary Tale ◽  
Phase Purity ◽  
X Ray ◽  
Phase Pure ◽  
Doped Materials

A comparison of X-ray powder diffraction and electron probe microanalyses on samples of Na- and K-doped Bi4V2O11 (BIMEVOX) solid electrolytes indicates some of the problems associated with using XRD to assess phase purity, especially in materials of variable composition such as BIMEVOXes. In this study both the Na- and K-doped materials appeared phase pure by XRD. EPMA indicated the Na-doped materials to be single phase with their expected compositions while the K-containing materials were not phase pure with very little K present in the main BIMEVOX phase.

Role of size, alio-/multi-valency and non-stoichiometry in the synthesis of phase-pure high entropy oxide (Co,Cu,Mg,Na,Ni,Zn)O

2020 ◽  
Vol 49 (21) ◽  
pp. 7123-7132 ◽  
Author(s):  
Nandhini J. Usharani ◽  
Rajat Shringi ◽  
Harshil Sanghavi ◽  
S. Subramanian ◽  
S. S. Bhattacharya
Keyword(s):  
Phase Formation ◽  
Single Phase ◽  
High Entropy ◽  
Phase Pure ◽  
Single Phase Formation

Presence of multivalency/non-stoichiometry to accommodate a different-sized cation and maintaining electroneutrality were identified as the critical criteria for single-phase formation in multicomponent/high entropy systems.

scholarly journals PHASE FORMATION AND SUPERCONDUCTIVITY OF Fe-TUBE ENCAPSULATED AND VACUUM-ANNEALED MgB2

2006 ◽  
Vol 20 (27) ◽  
pp. 1763-1769 ◽  
Author(s):  
K. P. SINGH ◽  
V. P. S. AWANA ◽  
MD. SHAHABUDDIN ◽  
M. HUSAIN ◽  
R. B. SAXENA ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Heating Temperature ◽  
Hold Time ◽  
Lattice Parameter ◽  
Hexagonal Structure ◽  
Synthesis Parameters ◽  
Phase Pure ◽  
The Right ◽  
Bell Shaped Curve

We report optimization of the synthesis parameters viz. heating temperature (TH), and hold time (t hold ) for vacuum-annealed (10-5 Torr) and LN 2 (liquid nitrogen) quenched MgB 2 compound. These are single-phase compounds crystallizing in the hexagonal structure (space group P 6/mmm ) at room temperature. Our XRD results indicated that for phase-pure MgB 2, the TH for 10-5 Torr annealed and LN 2-quenched samples is 750°C. The right stoichiometry i.e., MgB 2 of the compound corresponding to 10-5 Torr and TH of 750°C is found for the hold time (t hold ) of 2.30 hours. With varying t hold from 1–4 hours at fixed TH (750°C) and vacuum (10-5 Torr), the c-lattice parameter decreases first and later increases with t hold (hours) before a near saturation, while the a-lattice parameter first increases and later decreases beyond a t hold of 2.30 hours. The c/a ratio versus t hold plot showed an inverted bell-shaped curve, touching the lowest value of 1.141, which is the reported value for perfect stoichiometry of MgB 2. The optimized stoichimetric MgB 2 compound exhibited superconductivity at 39.2 K with a transition width of 0.6 K. In conclusion, the synthesis parameters for phase pure stoichimetric vacuum-annealed MgB 2 compound are optimized and are compared with widely-reported Ta tube encapsulated samples.

Cu/Zn/Al/Zr catalysts via phase-pure hydrotalcite-like compounds for methanol synthesis from carbon dioxide

2015 ◽  
Vol 11 ◽  
pp. 41-48 ◽  
Author(s):  
Peng Gao ◽  
Rongyong Xie ◽  
Hui Wang ◽  
Liangshu Zhong ◽  
Lin Xia ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Methanol Synthesis ◽  
Phase Pure

A Polymer Complexing Route for Low Temperature Synthesis of Perovskite Lanthanum Aluminate Powder

2010 ◽  
Vol 434-435 ◽  
pp. 863-867
Author(s):  
Shu Ai Li ◽  
Bill Bergman ◽  
Zhe Zhao
Keyword(s):  
Single Phase ◽  
Gelation Time ◽  
Secondary Phase ◽  
Processing Parameters ◽  
Molar Ratio ◽  
Complexing Agent ◽  
Low Temperature Synthesis ◽  
Powder Morphology ◽  
Lanthanum Aluminate ◽  
Phase Pure

Lanthanum aluminate powders were prepared via a polymer complexing method by using PEG as complexing agent. The LaAlO3 powder was characterized by XRD and SEM. The influence of processing parameters such as molar ratio of PEG monomers to metal cations (PEG:Men+) and aging process on the phase purity and powder morphology were investigated. The calcined powder with the PEG:Men+ ratio larger than 2:1 may contain the secondary phase, namely La2O3. The formation of phase pure LaAlO3 powder occurs when the PEG:Men+ ratio is 1:1 or enough gelation time is involved. Although the phase pure powder is obtained by this PEG method, all the single phase LaAlO3 powders are found to have seriously aggregated particles. The weakly agglomerated powder morphology is only found in the powders which contain La2O3.

scholarly journals Structural Chemistry of Some Phases in The YC-Ni-B System

1994 ◽  
Vol 376 ◽  
Author(s):  
B. C. Chakoumakos
Keyword(s):  
Powder Diffraction ◽  
Single Phase ◽  
Rietveld Analysis ◽  
Neutron Powder Diffraction ◽  
The Other ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Arc Melting ◽  
Phase Pure

ABSTRACTNiB, monoclinic Ni4B3, Ni2B and Ni3B were prepared by arc-melting and their roomtemperature crystal structures were refined by Rietveld analysis of neutron powder diffraction data. The NiB refinement is altogether new data. Although the B atoms in NiB form characteristic zigzag chains, the primary coordination of each atom by atoms of the other kind is similar and distinctively sevenfold, with one short (2.117 Å), two intermediate (2.152 Å), and four long (2.163 Å) bonds. Other samples with stoichiometries (YC)nNi2B2, n = 3, 4, did not yield single-phase material, but both x-ray and neutron powder diffraction suggest that the n = 4 structure is present in both of these samples. Phase-pure samples of these homologues may require non-stoichiometry and a more controlled thermal history than is attainable by arc melting.

Effects of V2O5 on the synthesis of Ba2Ti9O20 powders

2005 ◽  
Vol 20 (10) ◽  
pp. 2741-2744 ◽  
Author(s):  
Huixing Lin ◽  
Wei Chen ◽  
Lan Luo
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Eutectic Liquid ◽  
X Ray ◽  
Intermediate Phases ◽  
Phase Pure ◽  
Scanning Electron

Phase-pure Ba2Ti9O20 powders were made by doping 3 wt% of V2O5 to a Ba:Ti = 2:9 molar composition, and the effects of the dopant on the phase formation were investigated. The study shows that BaTiO3, BaTi2O5, and BaTi4O9 were the intermediate phases before the formation of Ba2Ti9O20 for samples with or without V2O5. However, with V2O5 doping, the temperature at which Ba2Ti9O20 occurred were lowered from 1150 to 1050 °C and single phase Ba2Ti9O20 powders was easily obtained at 1150 °C for 2 h. Microstructure of the powders was examined by field emission scanning electron microscopy. No evidence of V2O5–Ba2Ti9O20 solid-solution was found by x-ray diffraction and energy-dispersive spectroscopy. The benefit of V2O5 to facilitate the Ba2Ti9O20 synthesis is most probably due to a vanadium-containing eutectic liquid phase which accelerates the migration of reactant species.

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