Synthesis and Characterterization of Flower-Like NiO Nano-Architectures by Homogeneous Precipitation

2010 ◽  
Vol 434-435 ◽  
pp. 554-557 ◽  
Author(s):  
Ling Hong Luo ◽  
Ye Fan Wu ◽  
Fei Wei ◽  
Ji Jun Shi ◽  
Liang Cheng
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Average Diameter ◽  
Hexagonal Structure ◽  
Homogeneous Precipitation ◽  
Self Assembled ◽  
Xrd Patterns

Flower-like NiO powders with nano-architectures, self-assembled nano-sheets, were synthesized using Ni (NO3)2•4H2O and urea in mix solvents of ethanol and water by homogeneous precipitation. XRD patterns showed that the NiO powders were of hexagonal structure. FESEM and TEM confirmed that the average diameter of the flower-like NiO was 10μm, and the ultra-thin nano-sheets had micro-porous structure, with the thickness less than 100nm and the size of 2μm×3μm. Specific surface area (BET) was around 130.92m2/g.

Micro/Nanostructured α-Fe2O3 with Structural Enhanced Removal Capacity of Cr(VI) Ions

2012 ◽  
Vol 518-523 ◽  
pp. 1753-1756 ◽  
Author(s):  
Gang Liu ◽  
Quan Deng ◽  
Yong Yang ◽  
Hui Min Wang ◽  
Guo Zhong Wang
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Average Diameter ◽  
High Specific Surface Area ◽  
Removal Capacity

We have succeeded in preparing micro/nanostructured α-Fe2O3 spheres (MNFSs). The resulted MNFSs have an average diameter of about 5 µm, and are constructed by subunits of interlinked and elongated particles with a diameter of 20~60 nm. MNFSs show an obviously structural enhanced Cr(VI) removal capacity (5.88 mg/g) compared with nanoscaled (0.81 mg/g) and microscaled α-Fe2O3 (0.1 mg/g) due to its high specific surface area together with the special porous structure. Moreover, MNFSs show good availability of reusing to remove Cr(VI) ions.

scholarly journals High MB Solution Degradation Efficiency of FeSiBZr Amorphous Ribbon with Surface Tunnels

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3694 ◽  
Author(s):  
Qi Chen ◽  
Zhicheng Yan ◽  
Hao Zhang ◽  
Lai-Chang Zhang ◽  
Haijian Ma ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Free Volume ◽  
Specific Surface Area ◽  
Degradation Rate ◽  
High Efficiency ◽  
Amorphous Ribbon ◽  
Degradation Efficiency ◽  
Characteristic Distance

The as spun amorphous (Fe78Si9B13)99.5Zr0.5 (Zr0.5) and (Fe78Si9B13)99Zr1 (Zr1) ribbons having a Fenton-like reaction are proved to bear a good degradation performance in organic dye wastewater treatment for the first time by evaluating their degradation efficiency in methylene blue (MB) solution. Compared to the widely studied (Fe78Si9B13)100Zr0 (Zr0) amorphous ribbon for degradation, with increasing cZr (Zr atomic content), the as-spun Zr0, Zr0.5 and Zr1 amorphous ribbons have gradually increased degradation rate of MB solution. According to δc (characteristic distance) of as-spun Zr0, Zr0.5 and Zr1 ribbons, the free volume in Zr1 ribbon is higher Zr0 and Zr0.5 ribbons. In the reaction process, the Zr1 ribbon surface formed the 3D nano-porous structure with specific surface area higher than the cotton floc structure formed by Zr0 ribbon and coarse porous structure formed by Zr0.5 ribbon. The Zr1 ribbon’s high free volume and high specific surface area make its degradation rate of MB solution higher than that of Zr0 and Zr0.5 ribbons. This work not only provides a new method to remedying the organic dyes wastewater with high efficiency and low-cost, but also improves an application prospect of Fe-based glassy alloys.

Fabrication of an N-doped mesoporous bio-carbon electrocatalyst efficient in Zn–air batteries by an in situ gas-foaming strategy

2019 ◽  
Vol 55 (100) ◽  
pp. 15117-15120 ◽  
Author(s):  
Hong Wang ◽  
Wei Li ◽  
Zhiwei Zhu ◽  
Yijuan Wang ◽  
Pan Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrocatalytic Activity ◽  
High Specific Surface Area ◽  
Carbon Catalyst ◽  
Gas Foaming

An N-doped bio-carbon catalyst with a hierarchical interconnected macro/meso-porous structure and high specific surface area exhibited significantly enhanced electrocatalytic activity.

scholarly journals Preparation of Zirconia Nanofibers by Electrospinning and Calcination with Zirconium Acetylacetonate as Precursor

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1067 ◽  
Author(s):  
Vyacheslav V. Rodaev ◽  
Svetlana S. Razlivalova ◽  
Andrey O. Zhigachev ◽  
Vladimir M. Vasyukov ◽  
Yuri I. Golovin
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Heterogeneous Catalysts ◽  
Tetragonal Zirconia ◽  
Nitrogen Adsorption ◽  
Average Diameter ◽  
High Specific Surface Area ◽  
X Ray ◽  
Adsorption Analysis

For the first time, zirconia nanofibers with an average diameter of about 75 nm have been fabricated by calcination of electrospun zirconium acetylacetonate/polyacrylonitrile fibers in the range of 500–1100 °C. Composite and ceramic filaments have been characterized by scanning electron microscopy, thermogravimetric analysis, nitrogen adsorption analysis, energy-dispersive X-ray spectroscopy, and X-ray diffractometry. The stages of the transition of zirconium acetylacetonate to zirconia have been revealed. It has been found out that a rise in calcination temperature from 500 to 1100 °C induces transformation of mesoporous tetragonal zirconia nanofibers with a high specific surface area (102.3 m2/g) to non-porous monoclinic zirconia nanofibers of almost the same diameter with a low value of specific surface area (8.3 m2/g). The tetragonal zirconia nanofibers with high specific surface area prepared at 500 °C can be considered, for instance, as promising supports for heterogeneous catalysts, enhancing their activity.

Synthesis and Thermal Stability of HfO2 Nanoparticles

2010 ◽  
Vol 1256 ◽  
Author(s):  
Girija Shankar Chaubey ◽  
Yuan Yao ◽  
Julien Pierre Amelie Makongo Mangan ◽  
Pranati Sahoo ◽  
Pierre F. P. Poudeu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Large Scale ◽  
Average Diameter ◽  
Scale Production ◽  
Simple Method ◽  
Good Thermal Stability ◽  
Large Scale Production

AbstractA simple method is reported for the synthesis of monodispersed HfO2 nanoparticles by the ammonia catalyzed hydrolysis and condensation of hafnium (IV) tert-butoxide in the presence of surfactants at room temperature. Transmission electron microscopy shows faceted nanoparticles with an average diameter of 3-4 nm. As-synthesized nanoparticles are amorphous in nature and crystallize upon moderate heat treatment. The HfO2 nanoparticles have a narrow size distribution, large specific surface area and good thermal stability. Specific surface area was about 239 m2/g on as-prepared nanoparticle samples while those annealed at 500 °C have specific surface area of 221 m2/g indicating that there was no significant increase in particle size. This result was further confirmed by TEM images of nanoparticles annealed at 300 °C and 500 °C. X-ray diffraction studies of the crystallized nanoparticles revealed that HfO2 nanoparticles were monoclinic in structure. The synthetic procedure used in this work can be readily modified for large scale production of monodispersed HfO2 nanoparticles.

Synthesis and Photocatalytic Property of BiVO4/FeVO4 Composite Novel Photocatalyst

2010 ◽  
Vol 129-131 ◽  
pp. 784-788 ◽  
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Dong Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photocatalytic Property ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Triclinic Phase ◽  
Xrd Patterns

BiVO4/FeVO4 composite photocatalyst samples were prepared by calcining the mixture of FeVO4 and BiVO4 precusor which were prepared through liquid phase precipitation method for further increasing the photocatalytic efficiency of FeVO4. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microsoope（SEM）and specific surface area (BET). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under visible light. The XRD patterns indicate that BiVO4/FeVO4 composite photocatalysts consist of triclinic phase and the lattice was not distorted beacause of doping Bi. But the morphology change greatly and the specific surface area has little change. In the experimental conditions used, the optimal photocatalytic activity for all the prepared samples was reached when BiVO4 doping was 22 at%. The degradation rate of MO was increased by 20％ or so than that of pure FeVO4.

Effect of aging and alkali activator on the porous structure of a geopolymer

2014 ◽  
Vol 47 (1) ◽  
pp. 316-324 ◽  
Author(s):  
Prune Steins ◽  
Arnaud Poulesquen ◽  
Fabien Frizon ◽  
Olivier Diat ◽  
Jacques Jestin ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Inorganic Polymers ◽  
Porous Network ◽  
X Ray ◽  
Alkali Activator ◽  
Effects Of Aging

Nitrogen sorption and small- and wide-angle X-ray and neutron scattering techniques were used to study the porous structure of geopolymers, inorganic polymers synthesized by reaction of a strongly alkaline solution and an aluminosilicate source (metakaolin). The effects of aging and the use of alkali activators (Na+, K+) of different sizes were investigated at room temperature. The influence of aging time on the microstructure of both geopolymer matrixes was verified in terms of pore volume and specific surface area. The results suggested a refinement of the porosity and therefore a reduction in the pore volume over time. Regardless of the age considered, some characteristics of the porous network such as pore size, shape and distribution depend on the alkali activator used. Whatever the technique considered, the potassium geopolymer has a greater specific surface area than the sodium geopolymer. According to the scattering results, the refinement of the porosity can be associated with, first, a densification of the solid network and, secondly, a partial closure of the porosity at the nanometre scale. The kinetics are much slower for the sodium geopolymer than for the potassium geopolymer in the six months of observation.

scholarly journals Properties of materials for advanced technology of joint utilization of man-made waste

2019 ◽  
Vol 58 (6) ◽  
pp. 97-103
Author(s):  
Igor N. Tanutrov ◽  
◽  
Marina N. Sviridova ◽  
Sergey A. Lyamkin ◽  
Yury A. Chesnokov ◽  
...  
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Granulometric Composition ◽  
Average Diameter ◽  
Water Soluble ◽  
Advanced Technology ◽  
Particle Sizes ◽  
Main Components

With the aim of improving the technology of co-processing of red mud (RM) and oily mill scale free (OMS) using co-temporal methods and apparatus, including using equipment of the center «Ural-M», studied the physico-chemical properties of industrial wastes. The main components of RM are: Fe (35.7%) in the form of hematite and complex hydroalumination, Ca (11.0%) in the form of calcite and hydro-aluminosilicates, Al (6.8%) and Si (4.7%) in the composition of hydroalumination, Na (2.8%) in the form of hydroalumination, carbonate and hydroxide, Ti (2.5%) in the form of rutile. The sludge moisture content was 11.9%. The main components of the OMS are: Fe (71%) in the form of magnetite, wustite and hematite with a very small amount of fayalite. The contents of Si (in the form of quartz), Al and P (non-forming phases) are within 1-3%. Humidity OMS – 16.3%, the content of indelible organic matter – 4.0%. Granulometric composition of RM is characterized by high dispersion. With an average diameter of 1.6 µm, all particle sizes are in the range of 0.5-12 µm. Granulometric composition of OMS is characterized by complexity. With an average diameter of 8.6 µm, maxima of 0.9 µm and 15 µm and a minimum of about 1.2 µm are observed in the particle size distribution. The specific surface area of the materials is equal to RM 23.7 m2/g, and OMS – 1.9 m2/g. The change of waste properties after exposure to aqueous solutions of alkalis and acids neutralizing the effect of organic (OMS) and alkaline (RM) surface compounds was studied. Neutralization of aqueous sus¬pension with HCl solution leads to removal of alkaline film from the surface. As a result of the impact of reagents, there is a decrease in the content of water-soluble components in the processing products. At the same time, the average particle sizes of RM and OMS increase to 2 and 14 µm, respectively, and the specific surface area to 25.7 and 2.3 m2/g. The distribution of particle size of RM is almost constant, and the OMS is approximately 5 and 10% of the smoothed maximum and minimum in the area of at least 0.5 and 15 µm.

scholarly journals Research and simulation of hydrated alumina homogeneous precipitation and its application to obtain a carrier for catalysts in the petrochemical industry

2019 ◽  
Vol 4 (2) ◽  
pp. 72-79
Author(s):  
Pavel Kudryavtsev
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Colloidal Particles ◽  
Specific Model ◽  
Precipitation Process ◽  
Homogeneous Precipitation ◽  
Dissociative Mechanism ◽  
Hydrated Alumina ◽  
Hydrolytic Precipitation

The results of studies of the process of hydrated alumina homogeneous precipitation were presented in this work. The variants of this process are considered. The most convenient embodiment of this process is the precipitation of hydrated alumina from its salts with the use of auxiliary substances, such as urea. Urea hydrolysis allows a homogeneous precipitation process under the most mild conditions. It is shown that the process of hydrolytic precipitation in the aluminum salt-urea system proceeds according to the dissociative mechanism SN1. This article analyzes the regularities of precipitation of solid colloidal particles of hydrated metal oxides on the surface of various substrates. Two models of this process are proposed. The proposed α-model is a process of continuous nucleation of interaction centers, at random points of a free surface throughout the process. The proposed β-model provides for the instantaneous nucleation of these centers when they are randomly distributed over the entire surface of the substrate. Based on the proposed models, the average values of the following values are calculated: the thickness of the gel film; its roughness and specific surface area. The calculations carried out in the article showed that these parameters are universal functions of the degree of filling of the surface and do not depend on the specific model of the mechanism of the process. Studies have been conducted on the use of homogeneously precipitated aluminum hydroxide as a binder in the preparation of porous materials. The resulting materials have a developed specific surface area and porosity.

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