Effect of Calcination Temperature on Nickel/Alumina Catalysts

1992 ◽  
Vol 57 (10) ◽  
pp. 2073-2077 ◽  
Author(s):  
Khaliq Ahmed ◽  
Pronab Mistry
Keyword(s):  
Crystallite Size ◽  
Calcination Temperature ◽  
Hydrogen Adsorption ◽  
Nitrogen Adsorption ◽  
Nickel Catalysts ◽  
Surface Areas ◽  
Different Temperatures ◽  
Supported Nickel Catalysts ◽  
Alumina Catalysts

Alumina-supported nickel catalysts prepared by the methods of impregnation and coprecipitation and heated at four different temperatures showed that the optimal calcination temperature for both types of catalysts lies in the region of 623-673 K. Crystallite size measurements by XRD revealed that coprecipitated samples have larger crystallites than the impregnated samples. The total surface areas measured by nitrogen adsorption and the results of metal area measurements made by hydrogen adsorption are in agreement with the crystallite size results.

scholarly journals Benzene Hydrogenation Activities of Supported Nickel Catalysts in Relation to Their Chemisorption Properties

1995 ◽  
Vol 12 (2) ◽  
pp. 151-159 ◽  
Author(s):  
Th. El-Nabarawy ◽  
A.A. Attia ◽  
M.A. Hamada ◽  
A.M. Youssef
Keyword(s):  
Crystallite Size ◽  
Surface Area ◽  
Metal Surface ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Nickel Catalysts ◽  
Nickel Nitrate ◽  
Benzene Hydrogenation ◽  
Supported Nickel Catalysts

Samples of nickel on alumina (1.1–10.4 wt.% Ni) were prepared by impregnating alumina in hydrated nickel nitrate. The textural properties of the calcined catalysts have been determined from nitrogen adsorption at 77 K. Calcined catalysts were reduced prior to determination of the chemisorbed benzene at 308 K or chemisorbed hydrogen at 383 K. Hydrogenation of benzene was also determined at 473 K using the flow technique. The surface area of NiO/Al2O3 catalysts decrease and their mean pore radii increase with an increase in NiO content. These changes are more pronounced for catalysts containing more than 5% metal. Chemisorption of benzene proceeds via the formation of π-bonds with nickel. The chemisorption of hydrogen indicated that the percentage dispersion decreases and the crystallite size increases with an increase in metal loading. Dispersion, crystallite size and metal surface are important factors in determining the activity of supported nickel catalysts for benzene hydrogenation.

scholarly journals Characterization of Manganese Oxide/Alumina Catalysts

1995 ◽  
Vol 12 (3) ◽  
pp. 221-229 ◽  
Author(s):  
S.A. El-Hakam
Keyword(s):  
Manganese Oxide ◽  
Calcination Temperature ◽  
Manganese Content ◽  
Textural Properties ◽  
Catalytic Decomposition ◽  
Experimental Conditions ◽  
Surface Areas ◽  
Ft Ir ◽  
Mn Content ◽  
Alumina Catalysts

The effect of heat treatment of manganese oxide/alumina catalysts of various manganese content on the structural and textural properties and the catalytic decomposition of hydrogen peroxide were investigated. The FT-IR results have shown that depending on the calcination temperature and metal loading MnO2 and MnO3 are formed on the investigated samples. No spinel structure was detected under the experimental conditions. The surface areas were found to decrease with increasing calcination temperature and metal content up to 30 wt.% Mn. The mean pore radius increased with both calcination temperature and Mn content. The rate of catalytic decomposition of H2O2 was found to depend on the pH, the calcination temperature and the state of Mn on the catalyst surface.

scholarly journals Preparation Method of Co3O4Nanoparticles Using Degreasing Cotton and Their Electrochemical Performances in Supercapacitors

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Hongyan Xu ◽  
Libo Gao ◽  
Qiang Zhang ◽  
Junyang Li ◽  
Jiangtao Diwu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Adsorption ◽  
Electrochemical Performances ◽  
X Ray ◽  
Surface Areas ◽  
Synthetic Strategy ◽  
Different Temperatures ◽  
Specific Surface Areas

Co3O4nanoparticles were fabricated by a novel, facile, and environment-friendly carbon-assisted method using degreasing cotton. Structural and morphological characterizations were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The component of the sample obtained at different temperatures was measured by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Nitrogen adsorption and desorption isotherms were utilized to reveal the specific surface areas. The formation mechanism of Co3O4nanoparticles was also proposed, demonstrating that the additive degreasing cotton played an indispensable role in the process of synthesizing the sample. The resultant Co3O4sample calcined at 600°C exhibited superior electrochemical performance with better specific capacitance and long-term cycling life, due to its high specific surface areas and pores structures. Additionally, it has been proved that this facile synthetic strategy can be extended to produce other metal oxide materials (e.g., Fe3O4). As a consequence, the carbon-assisted method using degreasing cotton accompanied a promising prospect for practical application.

scholarly journals Enhanced Photocatalytic Activity of Hierarchical Macro-Mesoporous Anatase byZrO2Incorporation

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
M. L. García-Benjume ◽  
M. I. Espitia-Cabrera ◽  
M. E. Contreras-García
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Tween 20 ◽  
X Ray Diffraction ◽  
Surface Areas ◽  
Photocatalytic Effect ◽  
Different Temperatures ◽  
Adsorption Desorption

The effect of the addition of zirconia in the photocatalytic behaviour of titania is analysed. In order to increase the ways for reagent and product diffusion in the material, a sol-gel hydrothermal synthesis route using Tween-20 as a directing agent to obtain a hierarchical macro-mesoporous structure is proposed. Nanostructured macro-mesoporous TiO2/ZrO2photocatalyst with 0, 10, 20, 30, and 100% mol of ZrO2were obtained and calcined at different temperatures. The crystalline structure was analyzed by X-ray diffraction and TEM. The porosity was confirmed by SEM, TEM, and nitrogen adsorption-desorption isotherms. The worm-like mesoporous structure was confirmed by TEM. The specific surface areas obtained by Brunauer-Emmet-Teller method (BET) ranged from 125 to 180 m2/g. The Tween-20 total elimination from the structure by thermal treatment was confirmed by infrared spectroscopy and thermogravimetric analysis. Additionally, the photocatalytic effect of the zirconia addition was studied in the methylene blue (MB) degradation reaction, and the best photocatalytic activity was obtained in the sample with 10% mol of ZrO2, degrading up to 92% the MB.

scholarly journals Effects of doping with CeO2 and calcination temperature on physicochemical properties of the NiO/Al2O3 system

2009 ◽  
Vol 7 (4) ◽  
pp. 780-786
Author(s):  
Waleed Shaheen ◽  
A. El-Hendawy
Keyword(s):  
Catalytic Activity ◽  
Physicochemical Properties ◽  
Calcination Temperature ◽  
Opposite Effect ◽  
Nitrogen Adsorption ◽  
Degree Of Crystallinity ◽  
Calcination Temperatures ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
The Degree Of Crystallinity

AbstractThe effects of doping with CeO2 and calcination temperature on the physicochemical properties of the NiO/Al2O3 system have been investigated using DTA, XRD, nitrogen adsorption measurements at −196°C and decomposition of H2O2 at 30–50°C. The pure and variously doped solids were subjected to heat treatment at 300, 400, 700, 900 and 1000°C. The results revealed that the specific surface areas increased with increasing calcination temperature from 300 to 400°C and with doping of the system with CeO2. The pure and variously doped solids calcined at 300 and 400°C consisted of poorly crystalline NiO dispersed on γ-Al2O3. Heating at 700°C resulted in formation of well crystalline NiO and γ-Al2O3 phases beside CeO2 for the doped solids. Crystalline NiAl2O4 phase was formed starting from 900°C. The degree of crystallinity of NiAl2O4 increased with increasing the calcination temperature from 900 to 1000°C. An opposite effect was observed upon doping with CeO2. The NiO/Al2O3 system calcined at 300 and 400°C has catalytic activity higher than individual NiO obtained at the same calcination temperatures. The catalytic activity of NiO/Al2O3 system increased, progressively, with increasing the amount of CeO2 dopant and decreased with increasing the calcination temperature.

scholarly journals Effects of Li2O Doping on the Surface and Catalytic Properties of Co3O4–Fe2O3 Solids Precalcined at Different Temperatures

2000 ◽  
Vol 18 (3) ◽  
pp. 243-260 ◽  
Author(s):  
G.A. El-Shobaky ◽  
M.A. Shouman ◽  
M.N. Alaya
Keyword(s):  
Activation Energy ◽  
Catalytic Activity ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Nitrogen Adsorption ◽  
Surface Characteristics ◽  
Oxidation Of Co ◽  
Surface Areas ◽  
Different Temperatures ◽  
Activation Energy Of Sintering

The effects of Li2O treatment on the solid–solid interactions and the surface and catalytic properties of the Co3O4–Fe2O3 system have been studied using TG, DTA and XRD methods, nitrogen adsorption studies at −196°C and the catalytic oxidation of CO by O2 at 150–350°C. The results obtained showed that Li2O doping followed by precalcination at 500–1000°C enhanced the formation of cobalt ferrite to an extent proportional to the amount of dopant added (0.52–6.0 mol% Li2O). The solid–solid interaction leading to the formation of CoFe2O4 took place at temperatures ≥700°C in the presence of the Li2O dopant. Lithia doping modified the surface characteristics of the Co3O4–Fe2O3 solids, both increasing and decreasing their BET surface areas depending on the amount of dopant added and the precalcination temperature employed for the treated solids. The activation energy of sintering (ΔES) of cobalt/ferric mixed oxides was determined for the pure and doped solids from the variation in their specific surface areas as a function of the precalcination temperature. Both an increase and a decrease in the value of ΔES due to Li2O doping occurred depending on the amount of lithia added. The doping of Co3O4–FeO solids, followed by precalcination at 500°C, effected a significant increase (144%) in their catalytic activity towards CO oxidation by O2. Precalcination at 700–1000°C of the mixed oxide solids doped with Li2O (0.52 and 0.75 mol%) resulted in an increase in their catalytic activity which decreased upon increasing the amount of Li2O added above this limit. The activation energy of the catalyzed reaction was determined for the pure and variously doped solids studied.

scholarly journals INFLUENCE OF CALCINATION TEMPERATURE ON STRUCTURAL-DIMENSIONAL CHARACTERISTICS OF C,S-DOPED TiO2 NANOSTRUCTURES AND THEIR PHOTOCATALYTIC ACTIVITY IN THE CEFTAZIDIME AND DOXYCYCLINE PHOTODEGRADATION PROCESSES

2020 ◽  
Vol 86 (10) ◽  
pp. 95-119
Author(s):  
Natalia Romanovska ◽  
Petro Manoryk ◽  
Oleksandr Selyshchev ◽  
Pavlo Yaremov ◽  
Olexander Shylzshenko ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Crystallite Size ◽  
Tio2 Nanoparticles ◽  
Calcination Temperature ◽  
Sol Gel ◽  
High Photocatalytic Activity ◽  
Doped Tio2 ◽  
Different Temperatures ◽  
Tio2 Nanostructures

Mesoporous C, S-doped TiO2 nanostructures were obtained by solvothermal sol-gel method followed by calcination at different temperatures. It was found that with increasing calcination temperature, the crystallite size remains in the same range of 9–10 nm, while the morphology of TiO2 nanoparticles significantly changes, and the anatase content increases from 42% to 95%. At the same time the nanoparticle size (from 85 to 45 nm), the specific surface area (200–130 m2/g), the mesoporous area (from 170 to 70 m2/g), and the carbon (0.80–0.41%) and sulfur (1.39–0.89%) contents decrease. Varying the calcination temperature allows TiO2 nanostructures to be obtained with a certain balance of these structural-dimensional characteristics that provides high photocatalytic activity in the processes of ceftazidime and doxycycline photodegradation.

Pre-reforming of Liquefied Petroleum Gas over Magnesium Aluminum Mixed Oxide Supported Nickel Catalysts

2013 ◽  
Vol 33 (7) ◽  
pp. 1176-1182
Author(s):  
Xinxing WANG ◽  
Xueguang WANG ◽  
Xingfu SHANG ◽  
Wangxin NIE ◽  
Xiujing ZOU ◽  
...  
Keyword(s):  
Mixed Oxide ◽  
Nickel Catalysts ◽  
Liquefied Petroleum Gas ◽  
Supported Nickel Catalysts
Sign in / Sign up

Export Citation Format

Share Document