scholarly journals Catalytic Activity of Co3O4Nanomaterials with Different Morphologies for the Thermal Decomposition of Ammonium Perchlorate

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Li-Na Jin ◽  
Jian-Guo Wang ◽  
Xin-Ye Qian ◽  
Dan Xia ◽  
Ming-Dong Dong
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Ammonium Perchlorate ◽  
Volume Ratio ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cobalt Oxalate ◽  
Adsorption Desorption

Nano-Co3O4with different morphologies was successfully synthesized by annealing CoC2O4·2H2O precursors. The as-obtained samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and low-temperature nitrogen adsorption-desorption. It was found that the volume ratio of N,N-dimethylformamide (DMF) and water played an important role in the formation of cobalt oxalate precursors with different morphologies. After calcination in air, cobalt oxalate precursors converted to Co3O4nanomaterials while their original morphologies were maintained. The catalytic effect was investigated for nano-Co3O4with different morphologies on the thermal decomposition of ammonium perchlorate (AP) by differential scanning calorimeter (DSC). The results indicated that all products showed excellent catalytic activity for thermal decomposition of AP and the Co3O4nanorods with larger BET surface area and pore volume had the highest catalytic activity.

scholarly journals A Facile Method to Construct MXene/CuO Nanocomposite with Enhanced Catalytic Activity of CuO on Thermal Decomposition of Ammonium Perchlorate

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2457 ◽  
Author(s):  
Haifeng Zhao ◽  
Jing Lv ◽  
Junshan Sang ◽  
Li Zhu ◽  
Peng Zheng ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Ammonium Perchlorate ◽  
Photoelectron Spectra ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Improved Performance ◽  
Calcination Method

In this work, a mixing-calcination method was developed to facilely construct MXene/CuO nanocomposite. CuO and MXene were first dispersed in ethanol with sufficient mixing. After solvent evaporation, the dried mixture was calcinated under argon to produce a MXene/CuO nanocomposite. As characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectra (XPS), CuO nanoparticles (60–100 nm) were uniformly distributed on the surface and edge of MXene nanosheets. Furthermore, as evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the high-temperature decomposition (HTD) temperature decrease of ammonium perchlorate (AP) upon addition of 1 wt% CuO (hybridized with 1 wt% MXene) was comparable with that of 2 wt% CuO alone, suggesting an enhanced catalytic activity of CuO on thermal decomposition of AP upon hybridization with MXene nanosheets. This strategy could be further applied to construct other MXene/transition metal oxide (MXene/TMO) composites with improved performance for various applications.

The Different Morphology of Co3O4 Catalysts and Application in the Abatement of Carbon Monoxide

2021 ◽  
Vol 21 (12) ◽  
pp. 6082-6087
Author(s):  
Chih-Wei Tang ◽  
Hsiang-Yu Shih ◽  
Ruei-Ci Wu ◽  
Chih-Chia Wang ◽  
Chen-Bin Wang
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Adsorption Desorption

The increase of harmful carbon monoxide (CO) caused by incomplete combustion can affect human health even lead to suffocation. Therefore reducing the CO discharged by vehicles or factories is urgent to improve the air quality. The spinel cobalt (II, III) oxide (Co3O4) is an active catalyst for CO abatement. In this study, we tried to fabricate dispersing Co3O4 via the dispersion-precipitation method with acetic acid, formic acid, and oxalic acid as the chelating dispersants. Then, the asprepared samples were calcined at 300 ºC for 4 h to obtain active catalysts, and assigned as Co(A), Co(F) and Co(O) respectively, the amount of the dispersants used are labeled as I (0.12 mole), II (0.03 mole) and III (0.01 mole). For comparison, another CoAP sample was prepared via alkaliinduced precipitation and calcined at 300 ºC. All samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), scanning electron microscope (SEM), and nitrogen adsorption/desorption system, and the catalytic activity focused on the CO oxidation. The influence of chelating dispersant on the performance of abatement of CO was pursued in this study. Apparently, the results showed that the chelating dispersant can influence the catalytic activity of CO abatement. An optimized ratio of dispersant can improve the performance, while excess dispersant lessens the surface area and catalytic performance. The series of Co(O) samples can easily donate the active oxygen since the labile Co–O bonding and indicated the preferential performance than both Co(A) and Co(F) samples. The nanorod Co(O)-II showed preferential for CO oxidation, T50 and T90 approached 96 and 127 ºC, respectively. Also, the favorable durability of Co(O)-II sample maintains 95% conversion still for 50 h at 130 ºC and does not emerge deactivation.

scholarly journals Catalytic Performance of TiO2–Carbon Mesoporous-Derived from Fish Bones in Styrene Oxidation with Aqueous Hydrogen Peroxide as an Oxidant

2021 ◽  
Vol 16 (1) ◽  
pp. 88-96
Author(s):  
Mukhamad Nurhadi ◽  
Ratna Kusumawardani ◽  
Teguh Wirawan ◽  
Sumari Sumari ◽  
Sin Yuan Lai ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
Styrene Oxidation ◽  
Aqueous Hydrogen Peroxide ◽  
X Ray ◽  
Fish Bones ◽  
Adsorption Desorption ◽  
Kinetics Of

The catalytic performance of titania-supported carbon mesoporous-derived from fish bones (TiO2/CFB) has been investigated in styrene oxidation with aqueous H2O2. The preparation steps of (TiO2/CFB) catalyst involved the carbonization of fish bones powder at 500 °C for 2 h. followed by impregnation of titania using titanium(IV) isopropoxide (500 µmol) precursor, and calcined at 350 °C for 3 h. The physical properties of the adsorbents were characterized using Fourier transform infrared, X-ray diffraction (XRD), Scanning electron microscopy with energy dispersive X-ray (SEM-EDX), and nitrogen adsorption-desorption studies. The catalytic test was carried out using styrene oxidation with H2O2 as an oxidant at room temperature for 24 h. Its catalytic activity was compared with Fe2O3/CFB, CuO/CFB, TiO2, and CFB catalysts. It is demonstrated that the catalytic activity of TiO2/CFB catalyst has the highest compared to Fe2O3/CFB, CuO/CFB, TiO2, and CFB catalysts in the oxidation of styrene with styrene conversion ~23% and benzaldehyde selectivity ~90%. Kinetics of TiO2/CFB catalyzed oxidation of styrene has been investigated and mechanism for oxidation of styrene has been proposed. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA   License (https://creativecommons.org/licenses/by-sa/4.0). 

TiO2 Hollow Spheres Obtained under Autogenic Pressure at Elevated Temperature

2009 ◽  
Vol 79-82 ◽  
pp. 525-528 ◽  
Author(s):  
Ke Xun Li ◽  
Hong Liang Li ◽  
Jun Hua Zhao ◽  
Ying Chun Zhu ◽  
Xiu Song Zhao
Keyword(s):  
Elevated Temperature ◽  
Diffuse Reflectance ◽  
Hollow Spheres ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surfactant Additive ◽  
Tio2 Hollow Spheres ◽  
Adsorption Desorption

Carbon/TiO2 composites were prepared via the reaction under Autogenic Pressure at Elevated Temperature (RAPET) using alkoxides as precursor, and then porous TiO2 hollow spheres were derived after removing the carbon ingredient by calcination at 600°C. The influence of surfactant additives, including the addition ratio and the nature of the surfactants, on the morphology and the structures of the Carbon/TiO2 composites and the derived TiO2 were also studied with scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis diffuse reflectance spectrophotoscopy (DRS) and nitrogen adsorption-desorption measurements. The results revealed that the morphology of the products turned to spherical and then fusiform and the structures turned from hollow to solid with the increasing of surfactant additive. The BET surface area of the hollow TiO2 was modified from 12m2/g to 57m2/g after calcinations. The XRD investigation indicates that the phases of the TiO2 in both the carbon/TiO2 composites and the derived TiO2 hollow spheres are anatase.

scholarly journals Mechanochemical Preparation of Novel Polysaccharide-Supported Nb2O5 Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 38 ◽  
Author(s):  
Esther Rincon ◽  
Araceli Garcia ◽  
Antonio A. Romero ◽  
Luis Serrano ◽  
Rafael Luque ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Infrared Spectroscopy ◽  
Light Scattering ◽  
Reaction Time ◽  
Niobium Oxide ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Natural Sources ◽  
X Ray ◽  
Adsorption Desorption

Polysaccharides extracted from natural sources can be used as starting material for the preparation of nanoparticle supported composites. A novel family of bio-nanocomposites was mechanochemically synthesized by using niobium oxide and enzymatically produced polysaccharides. The structural, textural and surface properties of nanomaterials, were determined by X-Ray diffraction (XRD), nitrogen adsorption-desorption (N₂ porosimetry), pulse chromatography, infrared spectroscopy (ATR-IR) and dynamic light scattering (DLS). Selective oxidation of isoeugenol to vanillin was carried out to demonstrate the catalytic activity of the Nb-polysaccharides nanocomposites. Interestingly, most of our material showed high conversion of isoeugenol (60–70%) with selectivity to vanillin over 40%. The optimum conversion and selectivity were achieved with a reaction time between 8 and 24 h.

Application of raw and modified Uruguayan clays to phosphate adsorption for water remediation

MRS Advances ◽  
2018 ◽  
Vol 3 (61) ◽  
pp. 3543-3549
Author(s):  
Pablo González ◽  
Andrea C. De Los Santos ◽  
Jorge R. Castiglioni ◽  
María A. De León
Keyword(s):  
Nitrogen Adsorption ◽  
Pillared Clay ◽  
Water Remediation ◽  
Phosphate Adsorption ◽  
X Ray Diffraction ◽  
Order Model ◽  
Freundlich Model ◽  
X Ray ◽  
First Order ◽  
Adsorption Desorption

ABSTRACTA raw clay from Uruguay was modified with aluminium to obtain an aluminium pillared clay (Al-PILC). The solids were characterized by scanning electron microscopy, X-ray diffraction and nitrogen adsorption-desorption isotherms. The Al-PILC retained the typical laminar structure of montmorillonite. The specific surface area and the microporous volume of the Al-PILC, 235 m2 g-1 and 0.096 cm3 g-1, respectively, were much higher than those of the clay. The phosphate adsorption capacity of the Al-PILC was higher than those of the clay. The phosphate adsorption kinetic followed the pseudo-first-order model for both, the clay and the Al-PILC, and the phosphate adsorption isotherm for the Al-PILC fit the Freundlich model.

Structural and surface aspects of thermally treated copper aluminium mixed hydroxides

1991 ◽  
Vol 69 (10) ◽  
pp. 1511-1515 ◽  
Author(s):  
Awad I. Ahmed ◽  
S. E. Samra ◽  
S. A. El-Hakam
Keyword(s):  
Pore Structure ◽  
Copper Content ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Structure Surface ◽  
Adsorption Desorption

CuO–Al2O3 catalysts containing various amounts of copper oxide have been prepared by precipitation. The phase changes were studied by X-ray diffraction. The results obtained revealed that the thermal treatment of solid CuO–Al2O3 at 700 °C produced only crystalline CuO. Heating to 900 °C led to the formation of copper alumina spinel together with unreacted CuO and γ-Al2O3. The spinel content was found to increase with increasing copper content. Nitrogen adsorption–desorption isotherms on the calcined samples have been measured. Surface areas have been calculated and the pore structure analysed. The textural properties of the system were found to depend on both the copper content and the calcination temperature. Key words: CuO, Al2O3 catalysts, structure, surface area, pore structure.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

Preparation of Porous Carbon and its Composite Materials via the Reaction under Autogenic Pressure at Elevated Temperature (RAPET)

2018 ◽  
Vol 921 ◽  
pp. 60-64
Author(s):  
Ke Xun Li ◽  
Jiang Jiang Ma ◽  
Jie Zhang ◽  
Kun Jia ◽  
Bi Cheng Zhou ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Composite Materials ◽  
Porous Carbon ◽  
Nitrogen Adsorption ◽  
Inorganic Materials ◽  
Bet Surface Area ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
Discharge Performance ◽  
Adsorption Desorption

In this paper, we reported on the preparation of porous materials via a reaction under Autogenic Pressure at Elevated Temperature (RAPET) at 700°Cusing natural product and alkoxides as precursors. The RAPET is a new simple efficient method to prepare inorganic materials. The porous carbon and its composite materials were prepared via the method of RAPET using natural products such as sweet potato, coriander, the absorbent cotton and viscose fiber doped by tetrabutyl titanate (TBOT) and tetraethoxysilane (TEOS). The reaction temperature of RAPET was 700°C. The carbon and its composites were studied with scanning electron microscopy (SEM), X-ray diffraction (XRD) and nitrogen adsorption-desorption measurements. The BET surface area of the materials are different from 4m2/g to 405m2/g. The XRD investigation indicates that the phases of the TiO2 in the carbon/TiO2 composites are anatase. The materials show a certain charge-discharge performance.

scholarly journals Effect of the Organobentonite Filler on Structure and Properties of Composites Based on Hydroxyethyl Cellulose

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Olga V. Alekseeva ◽  
Anna N. Rodionova ◽  
Nadezhda A. Bagrovskaya ◽  
Alexander V. Agafonov ◽  
Andrew V. Noskov
Keyword(s):  
Tensile Properties ◽  
Composite Films ◽  
Nitrogen Adsorption ◽  
Hydroxyethyl Cellulose ◽  
X Ray Diffraction ◽  
Ir Spectrometry ◽  
X Ray ◽  
Mechanical Dispersion ◽  
Filling Agent ◽  
Adsorption Desorption

Organobentonite powder was synthesized and characterized using laser diffraction, X-ray diffraction, low-temperature nitrogen adsorption-desorption technique, and dynamic light scattering. Obtained powder was found as material with mesopores. The organobentonite particles were larger than pure bentonite one. Hydroxyethyl cellulose (HEC) was filled with organobentonite particles by mechanical dispersion, and produced composite films were researched by the number of methods. New data relating to structure, tensile properties, and antimicrobial activity of HEC/organobentonite composites were obtained. Using results of X-ray diffraction, the reflections assigned to crystal filler in polymer material were proved. Concentration effect of the filling agent on tensile properties of composite film was revealed. Data of infrared (IR) spectrometry indicated a decrease in the density of hydrogen-bond net in HEC/organobentonite composite as compared with pristine HEC. Using microbiological tests, it was found that the HEC/organobentonite films exhibited bacteriostatic action against S. aureus and fungistatic action against molds.

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