Effect of thermal treatment on catalytic properties of La0.9Ce0.1 0003

1987 ◽  
Vol 22 (8) ◽  
pp. 3037-3040 ◽  
Author(s):  
Kenji Tabata ◽  
Ikuo Matsumoto ◽  
Shigemi Kohiki
Keyword(s):  
Thermal Treatment ◽  
Catalytic Properties

scholarly journals The Importance of Thermal Treatment on Wet-Kneaded Silica–Magnesia Catalyst and Lebedev Ethanol-to-Butadiene Process

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 579
Author(s):  
Sang-Ho Chung ◽  
Adrian Ramirez ◽  
Tuiana Shoinkhorova ◽  
Ildar Mukhambetov ◽  
Edy Abou-Hamad ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Calcination Temperature ◽  
Catalytic Properties ◽  
Catalyst Preparation ◽  
Preparation Methods ◽  
Calcination Temperatures ◽  
Alternative Process ◽  
Magnesium Silicates

The Lebedev process, in which ethanol is catalytically converted into 1,3-butadiene, is an alternative process for the production of this commodity chemical. Silica–magnesia (SiO2–MgO) is a benchmark catalyst for the Lebedev process. Among the different preparation methods, the SiO2–MgO catalysts prepared by wet-kneading typically perform best owing to the surface magnesium silicates formed during wet-kneading. Although the thermal treatment is of pivotal importance as a last step in the catalyst preparation, the effect of the calcination temperature of the wet-kneaded SiO2–MgO on the Lebedev process has not been clarified yet. Here, we prepared and characterized in detail a series of wet-kneaded SiO2–MgO catalysts using varying calcination temperatures. We find that the thermal treatment largely influences the type of magnesium silicates, which have different catalytic properties. Our results suggest that the structurally ill-defined amorphous magnesium silicates and lizardite are responsible for the production of ethylene. Further, we argue that forsterite, which has been conventionally considered detrimental for the formation of ethylene, favors the formation of butadiene, especially when combined with stevensite.

Influence of the thermal treatment conditions and composition of bimetallic catalysts Fe—Pd/SiO2 on the catalytic properties in phenylacetylene hydrogenation

2016 ◽  
Vol 65 (2) ◽  
pp. 432-439 ◽  
Author(s):  
A. A. Shesterkina ◽  
L. M. Kozlova ◽  
O. A. Kirichenko ◽  
G. I. Kapustin ◽  
I. V. Mishin ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Bimetallic Catalysts ◽  
Catalytic Properties ◽  
Treatment Conditions

scholarly journals Surface and Catalytic Properties of NiO and Co3O4 Solids Doped with Cobalt and Nickel Ions

2002 ◽  
Vol 20 (5) ◽  
pp. 467-484
Author(s):  
G.A. El-Shobaky ◽  
A.M. Turky ◽  
A.M. Ghozza
Keyword(s):  
Particle Size ◽  
Thermal Treatment ◽  
Surface Area ◽  
Catalytic Properties ◽  
Excess Oxygen ◽  
Average Particle ◽  
Surface Excess ◽  
Nickel Ions ◽  
Nickel Species ◽  
Cobalt And Nickel

The effects of doping NiO and Co3O4 solids with cobalt and nickel species on their surface and catalytic properties were investigated. The amounts of dopant, in the form of the corresponding nitrate, were varied between 0.5–6.0 mol% cobalt ions and 2.0–6.0 mol% nickel ions. Pure and variously doped solids were subjected to thermal treatment at 300–700°C. The techniques employed were XRD, nitrogen adsorption at −196°C, decomposition of H2O2 at 30–50°C and estimation of the amount of surface excess oxygen on the variously prepared solids as determined by the hydrazine method. The results obtained revealed that the pure and variously doped NiO samples precalcined at 300°C consisted of a finely divided NiO phase having an average particle size of ca. 40 Å. Pure and variously doped Co3O4 specimens preheated at 500°C and 700°C were composed of a Co3O4 phase with a much bigger particle size (230 Å and 350 Å, respectively, for the solids precalcined at 500°C and 700°C). Doping of NiO followed by thermal treatment at 300°C and 500°C resulted in a measurable decrease in its BET surface area (19–23%), while doping of Co3O4 with nickel species followed by heating at 500°C and 700°C brought about a significant increase in its specific surface area (56–60%). Doping each of the NiO and Co3O4 solids with cobalt and nickel species greatly increased the amount of surface excess oxygen and effected a considerable increase in their catalytic activities. This increase was, however, much more pronounced in the case of NiO which attained a value of ca. 100-fold. Doping of NiO with cobalt species followed by thermal treatment at 300°C and 500°C decreased the activation energy (DE) of the catalyzed reaction to an extent proportional to the amount of dopant added. On the other hand, doping of Co3O4 with nickel species followed by thermal treatment at 500°C and 700°C did not change the value of DE. These results suggest that doping of Co3O4 with nickel species did not modify the mechanism of the catalyzed reaction but increased the concentration of catalytically active sites without changing their energetic nature.

scholarly journals Tuning of catalytic properties for electrooxidation of small organic molecules on Pt-based thin films via controlled thermal treatment

2019 ◽  
Vol 371 ◽  
pp. 96-105 ◽  
Author(s):  
D.V. Tripković ◽  
K.Dj. Popović ◽  
V.M. Jovanović ◽  
J.A. Nogueira ◽  
H. Varela ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Treatment ◽  
Organic Molecules ◽  
Catalytic Properties ◽  
Small Organic Molecules

scholarly journals Synthesis and Characterization of the Properties of Ceria Nanoparticles with Tunable Particle Size for the Decomposition of Chlorinated Pesticides

2020 ◽  
Vol 10 (15) ◽  
pp. 5224
Author(s):  
Kryštof Skrbek ◽  
Vilém Bartůněk ◽  
Michal Lojka ◽  
David Sedmidubský ◽  
Ondřej Jankovský
Keyword(s):  
Thermal Treatment ◽  
Crystallite Size ◽  
Catalytic Properties ◽  
Thin Layers ◽  
Precipitation Reaction ◽  
Ceria Nanoparticles ◽  
Chlorinated Pesticides ◽  
Selected Area Electron Diffraction ◽  
Vis Spectroscopy ◽  
Crystallite Sizes

Ceria nanoparticles are well known for their catalytic properties, which are commonly used in the automotive industry and other chemical branches. In this contribution, ceria nanoparticles were prepared by a simple precipitation reaction of cerium (IV) sulfate and ammonia. Such nanoparticles were very fine, with an approximate crystallite size of 2 nm. Crystallite sizes of these nanoparticles were adjusted by controlled heating, showing different catalytic properties. After thermal treatment, the surface area and crystallite size of nanoparticles were also compared by means of XRD and a sorption analyzer utilizing Brunauer–Emmet–Teller (BET). Morphology was studied by SEM, high-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED). Thin layers of ceria nanoparticles on silica glass and alumina ceramic underlays were also prepared and studied by SEM and EDS to demonstrate the possibility of ceria immobilization using thermal treatment of raw nanoparticles. The catalytic activity of the nanoparticles was tested on a 2,4,6-trichlorophenol aqueous solution and compared by UV–VIS spectroscopy.

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