scholarly journals Effect of Sulfation on Zirconia-Pillared Montmorillonite to the Catalytic Activity in Microwave-Assisted Citronellal Conversion

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Is Fatimah ◽  
Dwiarso Rubiyanto ◽  
Thorikul Huda
Keyword(s):  
Catalytic Activity ◽  
Surface Acidity ◽  
Total Pore Volume ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
Adsorption Method ◽  
X Ray ◽  
Pillared Montmorillonite ◽  
Microwave Assisted ◽  
Tandem Cyclization

Preparation of sulfated zirconia-pillared montmorillonite was carried out in two steps; zirconia pillarization and sulfation to zirconia-pillared montmorillonite. The prepared materials were characterized by using X-ray diffraction (XRD), measurement of the specific surface area, total pore volume and pore size distribution by the N2adsorption method, scanning electron microscopy-energy dispersive X-ray (SEM-EDX), and surface acidity determination by using pyridine adsorption-FTIR analysis. The activity of the materials as catalysts was evaluated for a microwave-assisted conversion of citronellal. The results showed that the prepared materials had a physicochemical character that promoted high catalytic activity to convert citronellal. From varied Zr content and study of the effect of sulfation on the activity, it was found that Zr content and sulfation increase the surface acidity of the material as shown by the higher total conversion and tendency to produce menthol as a product of the tandem cyclization-hydrogenation mechanism.

scholarly journals Copper-Containing Mixed Metal Oxides (Al, Fe, Mn) for Application in Three-Way Catalysis

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1344
Author(s):  
Tim Van Everbroeck ◽  
Radu-George Ciocarlan ◽  
Wouter Van Hoey ◽  
Myrjam Mertens ◽  
Pegie Cool
Keyword(s):  
Catalytic Activity ◽  
Spinel Structure ◽  
Mixed Oxides ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Application ◽  
Mixed Spinel ◽  
Co Precipitation ◽  
Three Way Catalysis

Mixed oxides were synthesized by co-precipitation of a Cu source in combination with Al, Fe or Mn corresponding salts as precursors. The materials were calcined at 600 and 1000 °C in order to crystallize the phases and to mimic the reaction conditions of the catalytic application. At 600 °C a mixed spinel structure was only formed for the combination of Cu and Mn, while at 1000 °C all the materials showed mixed spinel formation. The catalysts were applied in three-way catalysis using a reactor with a gas mixture containing CO, NO and O2. All the materials calcined at 600 °C displayed the remarkable ability to oxidize CO with O2 but also to reduce NO with CO, while the pure oxides such as CuO and MnO2 were not able to. The high catalytic activity at 600 °C was attributed to small supported CuO particles present and imperfections in the spinel structure. Calcination at 1000 °C crystallized the structure further which led to a dramatic loss in catalytic activity, although CuAl2O4 and CuFe2O4 still converted some NO. The materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, H2-Temperatrue Programmed Reduction (H2-TPR), N2-sorption and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX).

Isomerization of α-Pinene over Alumina-Pillared Montmorillonite

2013 ◽  
Vol 746 ◽  
pp. 49-52 ◽  
Author(s):  
Peng Quan Yao ◽  
Lin Hua Zhu ◽  
Jin Yang ◽  
Tian Si
Keyword(s):  
Basal Spacing ◽  
High Catalytic Activity ◽  
Temperature Reaction ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Pillared Montmorillonite ◽  
Catalytic Isomerization ◽  
Optimum Reaction

In this work, the liquid phase catalytic isomerization of α-pinene over alumina-pillared montmorillonitewas investigated, and the influence of reaction temperature, reaction time and amount of the catalyston the conversion of α-pinenewere discussed systematically, and the optimum reaction conditions forisomerization of α-pineneover alumina-pillared montmorillonitewere obtained. The basal spacing of thealumina-pillared montmorillonite was characterized by X-ray diffraction, and the liquid reactant was separated and identified by gas chromatography. The result showed that alumina-pillared montmorillonite with 1.83nm of basal spacing exhibited a high catalytic activity for the isomerization of α-pinene, and 97.4% conversion of α-pinene was achievedat 373K for 3hwhen the mass ratio of catalyst to α-pinene was 1/10.

Influence of Substituting Al by Mg-Co and Mn-Co on the Properties of AlPO4-5

1992 ◽  
Vol 57 (4) ◽  
pp. 750-755 ◽  
Author(s):  
Liao Changsheng
Keyword(s):  
Catalytic Activity ◽  
Infrared Spectra ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Surface Acidity ◽  
Chemical Compositions ◽  
Hydrothermal Crystallization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystallization Method

Two kinds of crystalline microporous metal aluminophosphate molecular sieves, magnesium cobalt aluminophosphate (MgCoAPO-5) and manganese cobalt aluminophosphate (MnCoAPO-5), were synthesized by hydrothermal crystallization method in order to improve the surface acidity and catalytic activity of AlPO4-5. The results of X-ray diffraction, infrared spectra and chemical compositions of MgCoAPO-5 and MnCoAPO-5 indicate that Mg-Co or Mn-Co enter the framework of AlPO4-5 molecular sieve without disrupting the microporous framework. However, the results of catalytic studies show that MgCoAPO-5 and MnCoAPO-5 possess much higher surface acidity and catalytic activity than the unmodified AlPO4-5.

scholarly journals Effect of Calcination Temperature on the Synthesis of ZrO2-Pillared Saponite to Catalytic Activity in Menthol Esterification

2018 ◽  
Vol 16 (1) ◽  
pp. 8 ◽  
Author(s):  
Is Fatimah ◽  
Dwiarso Rubiyanto ◽  
Nanda Candra Kartika
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Calcination Temperature ◽  
Surface Acidity ◽  
Physicochemical Characteristics ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcination Temperatures ◽  
Solid Acidity

The influence of calcination temperature on the synthesis of zirconia-pillared saponite (PILS) and on its catalytic activity in menthol esterification has been studied. Zirconia pillarization was conducted using zirconium tetraisopropoxide as a precursor and with calcination temperatures of 450, 600 and 700 °C. Evaluation of physicochemical characteristics at these varied temperatures was carried out by X-Ray Diffraction (XRD), surface area analysis, Scanning Electron Eicroscope (SEM) analysis, Differential Thermal Analysis (DTA) and total acidity. The obtained results indicate that the structure and surface acidity of saponite were strongly influenced by calcination temperature. The solid acidity and surface parameters such as specific surface area, pore volume, and pore radius play an important role in the total conversion and selectivity in menthol esterification.

Microstructure of Nanocrystalline Ceramics

1988 ◽  
Vol 132 ◽  
Author(s):  
H. Hahn ◽  
J. Logas ◽  
H. J. Höfler ◽  
Th. Bier ◽  
R. S. Averback
Keyword(s):  
Grain Growth ◽  
Sintering Temperature ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Green Body ◽  
X Ray Diffraction ◽  
Adsorption Method ◽  
X Ray ◽  
Nanocrystalline Ceramics ◽  
Scanning Electron

ABSTRACTThe microstructure of nanocrystalline (n-) TiO2 was studied as a function of sintering temperature up to 1273 K. Grain growth was monitored using x-ray diffraction and scanning electron microscopy. Measurements of density and permeability of He and Ar were also conducted. The specific surface area and the total pore volume were determined quantitatively using the nitrogen adsorption method. These measurements revealed that highly compacted n-TiO2 had green body densities as high as 75 % of bulk density and that sintering occurred at much lower temperatures than in conventional powder. Densification proceeded by loss of the small pores first. The possibilities of achieving high densities with limited grain growth will be discussed.

New organic–inorganic hybrid compounds based on [SiNb12V2O42]12− with high catalytic activity for styrene epoxidation

2017 ◽  
Vol 4 (8) ◽  
pp. 1397-1404 ◽  
Author(s):  
Ting-Ting Zhang ◽  
Xiao Zhang ◽  
Ying Lü ◽  
Guo-Dong Li ◽  
Li-Na Xiao ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
High Catalytic Activity ◽  
Styrene Epoxidation ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Inorganic Hybrid ◽  
X Ray ◽  
Hybrid Compounds

A series of new organic–inorganic hybrid compounds based on [SiNb12V2O42]12− have been obtained under hydrothermal conditions and characterized by IR, XRD, and single crystal X-ray diffraction analysis.

scholarly journals Effect of Chemical Composition on the Structure and Catalytic Behaviour of AlPO4 and Al2O3–AlPO4 Mixed Catalysts

2002 ◽  
Vol 20 (2) ◽  
pp. 131-140 ◽  
Author(s):  
F.Sh. Mohamed ◽  
H.H. Kiwan ◽  
M.R. Mostafa
Keyword(s):  
Catalytic Activity ◽  
Chemical Composition ◽  
Surface Area ◽  
Surface Acidity ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Texture Surface ◽  
Pore Widening ◽  
Catalytic Behaviour

AlPO4 and Al2O3–AlPO4 mixed catalysts of different composition (Al/P > 1) were prepared and calcined in the temperature range 350–650°C. Such catalysts were characterized by DTA and X-ray diffraction methods, and by nitrogen adsorption studies at −196°C. Their acidity was determined using a calorimetric titration method while their catalytic activity towards the dehydration of isopropanol was determined using a pulse microcatalytic technique. The data obtained from XRD studies showed that pure AlPO4 when calcined at 650°C had a rather low crystallinity with its crystalline structure (which is of the α-cristobalite type) being characterized by poorly developed peaks. However, significant changes in the texture, surface acidity and catalytic activity were observed as a result of changing the chemical composition of the solid, with the surface area, total pore volume and surface acidity generally increasing with increasing alumina content. Sintering commenced above 550°C leading to a decrease in the surface area and to pore widening. Dehydration of isopropanol appeared to be insensitive to the structure of the catalysts investigated but was related to the surface acid density.

scholarly journals A study on the synthesis of MIL-100(Fe) and its application in the catalytic degradation of methylene blue

2018 ◽  
Vol 1 (T5) ◽  
pp. 149-157
Author(s):  
Thien Vinh Tran ◽  
Dien Huu Huynh
Keyword(s):  
Methylene Blue ◽  
Fourier Transform ◽  
Catalytic Activity ◽  
Oxidation Reaction ◽  
Hydrothermal Process ◽  
Catalytic Degradation ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir

In the present paper, a study on the synthesis of MIL-100(Fe) by hydrothermal process and its application in the catalytic degradation of methylene blue (MB) was demonstrated. The obtained samples were characterized by X-ray Diffraction (XRD), scaning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR), Brunauer, Emmett and Teller (BET) and energy-dispersive X-ray spectroscopy (EDX). The results showed that the synthesized MIL- 100(Fe) exhibited high crystallinity and surface area. Its catalytic activity was evaluated by measuring the rate of conversion of MB after oxidation reaction by H2O2. The results indicated that the MIL-100(Fe) showsed high catalytic activity for the oxidation reaction of MB and at pH = 10, MB was degraded almost completely after after 3 hours of presence of the catalyst.

scholarly journals Surface Characterization and Catalytic Activity of Alumina and Alumina-Supported ZnSO4 Catalysts Prepared from Different Alumina Sources

2002 ◽  
Vol 20 (7) ◽  
pp. 695-705
Author(s):  
Farid Sh. Mohamed
Keyword(s):  
Catalytic Activity ◽  
Surface Characterization ◽  
Surface Acidity ◽  
Catalyst Activity ◽  
Total Pore Volume ◽  
Acid Sites ◽  
Aluminium Chloride ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Ft Ir

Three alumina samples were prepared from different sources including aluminium isopropoxide, aluminium chloride and aluminium nitrate, and were then used to prepare supported ZnSO4 catalysts via the impregnation method. The alumina and ZnSO4-supported samples were characterized by X-ray diffraction (XRD), FT-IR spectroscopy and nitrogen physisorption methods. Dehydration of 1-butanol and the cracking of cumene were undertaken over the prepared samples using a pulse microcatalytic technique. For a given alumina sample, the surface area and total pore volume decreased continuously with increasing ZnSO4 content. Loading alumina samples with ZnSO4 improved their dehydration and cracking activities. The source of alumina played a role in determining the surface acidity and catalyst activity of alumina and alumina-supported ZnSO4 catalysts. Impregnation of ZnSO4 on alumina samples resulted in an increase in the concentration of Lewis sites and the creation of Brönsted acid sites on their surfaces. The catalytic activity of the investigated catalysts was found to depend strongly on both the chemical composition and the type of acid site present on the catalyst surface.

Catalytic Performance of CuPd/BNNS Nanocatalysts Prepared by Microwave-Assisted Synthesis for the Reduction of Cr(VI)

NANO ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. 2050142
Author(s):  
Xiaorui Zhang ◽  
Guohua Li ◽  
Enyan Hu ◽  
Longjun Xu ◽  
Siping Gan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Noble Metal ◽  
Metal Content ◽  
Reaction Rate ◽  
Microwave Assisted Synthesis ◽  
High Catalytic Activity ◽  
X Ray ◽  
Microwave Assisted ◽  
Boron Nitride Nanosheet

Copper-palladium (CuPd)/boron nitride nanosheet (BNNS) nanocatalysts were successfully prepared by a microwave-assisted method by using BNNSs as a carrier. These catalysts with a low noble metal content had a high catalytic activity for Cr(VI) reduction at room temperature. The reaction rate reached 0.04044[Formula: see text]s[Formula: see text], which was approximately 2.5 times that of Cu8Pd2/rGO with the same metal loading amount. Compared with the previously reported PdCu/NG nanocatalysts with a high noble metal content, the reaction rate increased more than five times. This is of great significance to the application of supported metal composites in environmental catalysis. The structure and morphology of the catalyst was characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Several types of control experiments showed that the catalytic activity of the catalysts was not only influenced by the synergistic effect of bimetallic CuPd and metal-BNNSs but also related to the catalytic effect of the BNNS carrier itself.

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