Influence of phase composition and particle size of atomised Ni–Al alloy samples on the catalytic performance of Raney-type nickel catalysts

2009 ◽  
Vol 356 (2) ◽  
pp. 154-161 ◽  
Author(s):  
F. Devred ◽  
A.H. Gieske ◽  
N. Adkins ◽  
U. Dahlborg ◽  
C.M. Bao ◽  
...  
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Al Alloy ◽  
Type Nickel

Synchrotron X-ray microtomography of Raney-type nickel catalysts prepared by gas atomisation: Effect of microstructure on catalytic performance

2011 ◽  
Vol 163 (1) ◽  
pp. 13-19 ◽  
Author(s):  
F. Devred ◽  
G. Reinhart ◽  
G.N. Iles ◽  
B. van der Klugt ◽  
N.J. Adkins ◽  
...  
Keyword(s):  
Nickel Catalysts ◽  
Catalytic Performance ◽  
X Ray ◽  
Type Nickel ◽  
Effect Of Microstructure

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

scholarly journals A Thermally Conductive Pt/AAO Catalyst for Hydrogen Passive Autocatalytic Recombination

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 491
Author(s):  
Alina E. Kozhukhova ◽  
Stephanus P. du Preez ◽  
Aleksander A. Malakhov ◽  
Dmitri G. Bessarabov
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Combustion Temperature ◽  
Volume Fraction ◽  
Morphological Characteristics ◽  
Al Alloy ◽  
Impregnation Method ◽  
Case Scenario ◽  
Worst Case ◽  
Thermal Distribution

In this study, a Pt/anodized aluminum oxide (AAO) catalyst was prepared by the anodization of an Al alloy (Al6082, 97.5% Al), followed by the incorporation of Pt via an incipient wet impregnation method. Then, the Pt/AAO catalyst was evaluated for autocatalytic hydrogen recombination. The Pt/AAO catalyst’s morphological characteristics were determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average Pt particle size was determined to be 3.0 ± 0.6 nm. This Pt/AAO catalyst was tested for the combustion of lean hydrogen (0.5–4 vol% H2 in the air) in a recombiner section testing station. The thermal distribution throughout the catalytic surface was investigated at 3 vol% hydrogen (H2) using an infrared camera. The Al/AAO system had a high thermal conductivity, which prevents the formation of hotspots (areas where localized surface temperature is higher than an average temperature across the entire catalyst surface). In turn, the Pt stability was enhanced during catalytic hydrogen combustion (CHC). A temperature gradient over 70 mm of the Pt/AAO catalyst was 23 °C and 42 °C for catalysts with uniform and nonuniform (worst-case scenario) Pt distributions. The commercial computational fluid dynamics (CFD) code STAR-CCM+ was used to compare the experimentally observed and numerically simulated thermal distribution of the Pt/AAO catalyst. The effect of the initial H2 volume fraction on the combustion temperature and conversion of H2 was investigated. The activation energy for CHC on the Pt/AAO catalyst was 19.2 kJ/mol. Prolonged CHC was performed to assess the durability (reactive metal stability and catalytic activity) of the Pt/AAO catalyst. A stable combustion temperature of 162.8 ± 8.0 °C was maintained over 530 h of CHC. To confirm that Pt aggregation was avoided, the Pt particle size and distribution were determined by TEM before and after prolonged CHC.

Catalytic performance of manganese-promoted nickel catalysts for the steam reforming of tar from biomass pyrolysis to synthesis gas

Fuel ◽  
2013 ◽  
Vol 103 ◽  
pp. 122-129 ◽  
Author(s):  
Mitsuru Koike ◽  
Chiaki Ishikawa ◽  
Dalin Li ◽  
Lei Wang ◽  
Yoshinao Nakagawa ◽  
...  
Keyword(s):  
Synthesis Gas ◽  
Steam Reforming ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Biomass Pyrolysis

Microbial-Induced Mineralization of Zinc Ions Based on the Degradation of Toluene and Its Characterization

2021 ◽  
Vol 13 (4) ◽  
pp. 656-661
Author(s):  
Yiyan Lv ◽  
Qiwei Zhan ◽  
Xiaoniu Yu
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Surface Morphology ◽  
Organic Compounds ◽  
Low Cost ◽  
Zinc Ion ◽  
Zinc Ions ◽  
Quick Response ◽  
Zinc Carbonate ◽  
Carbonate Ions

Microbial-induced degradation of aromatic organic compounds and mineralization of zinc ions have attracted much attention because of its low cost, simple operation and quick response. This research, toluene was decomposed and made the concentration of carbonate ions increased accordingly by the enzymatic pressing of microorganisms, meanwhile carbonate ions mineralized zinc ions into carbonate precipitations. The composition and microstructure were analyzed systematically. The analysis results indicated that carbonate precipitations, basic zinc carbonate, could be successfully prepared by microbial method. The particle size of basic zinc carbonate was nanometer, and its shape was near-spherical. Furthermore, the phase composition, functional groups and surface morphology of the precipitations prepared by different methods were basically the same. This work provided a new method for remediation of zinc ion pollution based on the degradation of toluene.

scholarly journals Study of the properties of Ce3+-doped fluoride nanophosphors: phase composition, morphology, luminescence

2021 ◽  
Vol 2056 (1) ◽  
pp. 012048
Author(s):  
A M Dorokhina ◽  
V V Bakhmetyev ◽  
H Kominami ◽  
A Toru ◽  
M Hisashi
Keyword(s):  
Particle Size ◽  
Photodynamic Therapy ◽  
Phase Composition ◽  
Polyethylene Glycol ◽  
Ethylene Glycol ◽  
Solvothermal Synthesis ◽  
Luminescent Properties ◽  
Optimal Duration ◽  
Oncological Diseases ◽  
Synthesis Medium

Abstract To date, nanophosphors have found application in various fields, one of which is medicine. These phosphors were developed with the aim to become one of the components of a drug for photodynamic therapy of oncological diseases. The aim of this work was to study the effect of the duration, environment, and stabilizers of solvothermal synthesis on the microstructure and luminescent properties of the YF3:Ce nanophosphor. The solvothermal synthesis technique was carried out in three different media: water, ethanol, and ethylene glycol. The optimal duration of the synthesis was also determined (the synthesis was carried out at a temperature of 200°C for 4…20 hours). The dependence of the YF3 luminescence on the phase composition and the solvothermal synthesis medium was studied. Using SEM, the morphology and particle size of YF3:Ce phosphors were studied depending on different stabilizers (polyethylene glycol, polyethyleneimine, polyvinylpyrrolidone). The luminescence intensity of YF3:Ce and Na(Y1,5Na0,5)F6:Ce samples was compared.

scholarly journals Ni-Based Complexes in Selective Ethylene Oligomerization Processes

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 498
Author(s):  
Giyjaz E. Bekmukhamedov ◽  
Aleksandr V. Sukhov ◽  
Aidar M. Kuchkaev ◽  
Dmitry G. Yakhvarov
Keyword(s):  
High Density Polyethylene ◽  
Petrochemical Industry ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Ethylene Oligomerization ◽  
Linear Low Density Polyethylene ◽  
Main Method ◽  
The World ◽  
World Demand ◽  
Alpha Olefins

Linear alpha-olefins are widely used in the petrochemical industry and the world demand for these compounds increases annually. At present, the main method for producing linear alpha-olefins is the homogeneous catalytic ethylene oligomerization. This review presents modern nickel catalysts for this process, mainly systems for obtaining of one of the most demanded oligomer—1-butene—which is used for the production of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE). The dependence of the catalytic performance on the composition and the structure of the used activated complexes, the electronic and coordination states of the nickel center was considered.

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