scholarly journals Role of CA-EDTA on the Synthesizing Process of Cerate-Zirconate Ceramics Electrolyte

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nur Athirah Abdullah ◽  
Sharizal Hasan ◽  
Nafisah Osman
Keyword(s):  
Thermal Decomposition ◽  
Citric Acid ◽  
Chelating Agents ◽  
Sol Gel ◽  
Decomposition Temperature ◽  
Metal Nitrate ◽  
Molar Ratio ◽  
Calcination Temperatures ◽  
Decomposition Behaviour

The role of a combination between citric acid (CA) and ethylenediaminetetra acetic acid (EDTA) as chelating agents in preparation of BaCe0.54Zr0.36Y0.1O2.95powder by a modified sol-gel method is reported. The precursor solutions were prepared from metal nitrate salts (M+), chelating agents (C), and ethylene glycol (EG) at molar ratio of M+ : C : EG = 3 : 2 : 3. Chemical and phase transformation of samples during thermal decomposition were analyzed by thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. TGA results show that the sample prepared by a combination of CA-EDTA exhibited the lowest thermal decomposition temperature,Ttdsince there was no significant weight loss after 750°C. After calcined at 1100°C, the carbonates residue remained in the samples as proven by FTIR results. It was found that the used combination of CA-EDTA acts as a better combustion reagent to increase the reaction rate and influence the thermal decomposition behaviour compared to a single citric acid and EDTA, respectively. Apparently, calcination temperatures above 1100°C are needed to produce a pure perovskitic BaCe0.54Zr0.36Y0.1O2.95.

scholarly journals Photocatalytic Improvement under Visible Light inTiO2Nanoparticles by Carbon Nanotube Incorporation

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mathana Wongaree ◽  
Siriluk Chiarakorn ◽  
Surawut Chuangchote
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Sol Gel ◽  
Multiwall Carbon Nanotubes ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Calcination Temperatures ◽  
Photocatalytic Activities ◽  
Multiwall Carbon

Photocatalytic activity ofTiO2nanoparticles was successfully enhanced by addition of multiwall carbon nanotubes (MWCNT) to make CNT/TiO2nanocomposites by sol-gel method at ambient temperature. CNT treated by HNO3 : H2SO4treatment (1 : 3 v/v) was mixed withTiO2nanoparticles at various molar ratios and calcination temperatures. The optimal molar ratio of CNT : TiO2was found at 0.05 : 1 by weight. The optimal calcination condition was 400°C for 3 h. From the results, the photocatalytic activities of CNT/TiO2nanocomposites were determined by the decolorization of 1 × 10−5 M methylene blue (MB) under visible light. CNT/TiO2nanocomposites could enhance the photocatalytic activity and showed faster for the degradation of MB with only 90 min. The degradation efficiency of the MB solution with CNT/TiO2nanocomposite achieved 70% which was higher than that with pristineTiO2(22%). This could be explained that CNT preventsTiO2from its agglomeration which could further enhance electron transfer in the composites. In addition, CNT/TiO2nanocomposites had high specific surface area (202 m2/g) which is very promising for utilization as a photocatalyst for environmental applications.

scholarly journals The Role of Nitrate on the Sol-Gel Spread Self-Combustion Process and Its Effect on the NH3-SCR Activity of Magnetic Iron-Based Catalyst

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 314
Author(s):  
Xing Ning ◽  
Zhi-bo Xiong ◽  
Bin Yang ◽  
Wei Lu ◽  
Shui-mu Wu
Keyword(s):  
Nitric Acid ◽  
Citric Acid ◽  
Sol Gel ◽  
Nox Reduction ◽  
Combustion Process ◽  
Catalytic Performance ◽  
Metal Nitrate ◽  
Acid Sites ◽  
Complexing Agent ◽  
Nh3 Scr

Sol-gel spread self-combustion is the burning of the complexing agent in dried gel and the oxidant. Meanwhile, high temperature takes place during the combustion process, which is harmful to the pore structure of the catalyst. The nitrate from metal nitrate precursors as an oxidant could participate in the spread of the self-combustion process. Therefore, the influence of nitrate from metal nitrate on the spread self-combustion of an iron–cerium–tungsten citric acid gel and its catalytic performance of NOx reduction were investigated by removing nitrate via the dissolution of washing co-precipitation with citric acid and re-introducing nitric acid into the former solution. It was found that the removal of nitrate contributes to enhancing the NH3–SCR activity of the magnetic mixed oxide catalyst. The NOx reduction efficiency was close to 100% for Fe85Ce10W5–CP–CA at 250 °C while the highest was only 80% for the others. The results of thermal analysis demonstrate that the spread self-combustion process of citric acid dried gel is enhanced by re-introducing nitric acid into the citric acid dissolved solution when compared with the removal of nitrate. In addition, the removal of nitrate helps in the formation of γ-Fe2O3 crystallite in the catalyst, refining the particle size of the catalyst and increasing its pore volume. The removal of nitrate also contributes to the formation of Lewis acid sites and Brønsted acid sites on the surface of the catalyst compared with the re-introduction of nitric acid. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) demonstrates that both Eley–Rideal (E–R) and Langmuir–Hinshelwood (L–H) mechanisms exist over Fe85Ce10W5–CP–CA at 250 °C with E–R as its main mechanism.

Cooperative Assembly of Metal Nitrate and Citric Acid with Block Copolymers: Role of Carbonate Conversion Temperature on the Mesostructure of Ordered Porous Oxides

2015 ◽  
Vol 119 (22) ◽  
pp. 12138-12148 ◽  
Author(s):  
Michael C. Burroughs ◽  
Sarang M. Bhaway ◽  
Pattarasai Tangvijitsakul ◽  
Kevin A. Cavicchi ◽  
Mark D. Soucek ◽  
...  
Keyword(s):  
Citric Acid ◽  
Block Copolymers ◽  
Metal Nitrate ◽  
Porous Oxides ◽  
Cooperative Assembly ◽  
Ordered Porous ◽  
Conversion Temperature

scholarly journals Effect of 1,4-Naphthalenedicarboxylic Acid Derivative on Crystallization and Performances of Poly(L-lactide)

2021 ◽  
Vol 58 (1) ◽  
pp. 57-68
Author(s):  
Lisha Zhao ◽  
Jun Qiao ◽  
Xueling Shan ◽  
Yanhua Cai ◽  
Jie Zhang
Keyword(s):  
Thermal Decomposition ◽  
Melting Temperature ◽  
Crystallization Temperature ◽  
Crystallization Rate ◽  
Decomposition Temperature ◽  
Organic Additive ◽  
Onset Crystallization Temperature ◽  
Nucleation Sites ◽  
Biodegradable Poly

In this work, biodegradable Poly(L-lactide) (PLLA) was modified through adding a new organic additive N, N -bis(benzoyl) 1, 4-naphthalenedicarboxylic acid dihydrazide (NABH). A comparison on crystallization of the pure PLLA and PLLA/NABH revealed that the NABH as effective heterogeneous nucleation sites enhanced PLLA𠏋 crystallization, and an increase of NABH loading was able to further accelerate crystallization rate of PLLA; whereas a faster cooling rate was not conducive to PLLA𠏋 crystallization, but the appearance of obvious crystallization peak upon cooling at 30şC/min confirmed the advanced enhancing role of NABH for PLLA crystallization again. The investigation on influence of the final melting temperature on the crystallization behavior of PLLA showed that the 170 şC was optimum final melting temperature for enhancing crystallization, even the onset crystallization temperature of PLLA/NABH were higher than 150şC. The melting processes of PLLA/NABH after different crystallization not only could reflect the previous crystallization, but also depended on crystallization temperature and heating rate. Thermal decomposition results showed that the existence of NABH slightly weakened thermal stability of PLLA, and the maximum difference in onset thermal decomposition temperature was only 9.4şC comparing with the pure PLLA. However, the presence of NABH in PLLA matrix seriously weakened optical property.

Process for Non-Agglomerated Nanometer-Sized Barium Titanate Powders by Sol-Gel Auto-Igniting Synthesis

2007 ◽  
Vol 280-283 ◽  
pp. 613-616 ◽  
Author(s):  
Qing Zhi Yan ◽  
Xin Tai Su ◽  
Wen Feng Zhang ◽  
Chang Chun Ge
Keyword(s):  
Citric Acid ◽  
Sol Gel ◽  
Particle Morphology ◽  
Molar Ratio ◽  
Hydroxyl Groups ◽  
Compound System ◽  
Organic Fuel ◽  
Acid Chelate ◽  
Hard Agglomerate ◽  
Scanning Electron

Non-agglomerated nano-sized BaTiO3 powders were prepared by a 3 step decomposition of barium titanyl citric acid chelate derived from Ba(NO3)2-TiO(NO3)2-citric acid-NH4NO3 based complex compound system. The 1st step was the thermal treatment of chelate wet gel at 150°C for 40min to remove water and non-bridging hydroxyl groups and to form expanded gel intermediate. The 2nd step was the decomposition of the organic fuel by igniting expanded gel intermediate at 300°C. The 3rd step was the formation of the high purity BaTiO3 by calcining the decomposed powders at 700°C for 2 hours. The most expanded gel intermediate was found to be a decisive factor for the elimination of hard agglomerate. In addition, the initial oxidant/fuel molar ratio was shown to strongly influence the characteristics of the powders thus obtained. The optimum oxidant/fuel value was 3 for obtaining non-agglomerated pure BaTiO3 powders with a particle size of 50 nm. The agglomerate degree of BaTiO3 powders was determined by particle morphology and uniformity of the green compact microstructure observed by field emission scanning electron microscopy and scanning electron microscope.

scholarly journals Magnetic and dielectric properties of Ca-substituted BiFeO3 nanoferrites by the sol-gel method

2018 ◽  
Vol 16 (1_suppl) ◽  
pp. 93-100 ◽  
Author(s):  
Jinpei Lin ◽  
Zeping Guo ◽  
Mei Li ◽  
Qing Lin ◽  
Kangling Huang ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Sol Gel ◽  
Diffraction Peak ◽  
Multiferroic Material ◽  
Superconducting Quantum Interference Device ◽  
X Ray ◽  
Calcination Temperatures ◽  
Main Diffraction Peak ◽  
Microwave Network Analysis

Background: A multiferroic material can simultaneously show two or more basic magnetic properties, including ferromagnetism, antiferromagnetism, and ferroelectricity. BiFeO3 is a multiferroic material with a rhombohedral distorted perovskite structure. Doping can reduce the volatility of Bi and greatly improve the magnetoelectric properties of BiFeO3. Methods: To investigate the influence of the doping content we used the following analytical methods: X-ray powder diffraction (XRD), scanning electron microscopy (SEM), microwave network analysis (PNA-N5244A), and the Superconducting Quantum Interference Device (Quantum Design MPMS) test. Results: With the increase of Ca2+ concentration in the solution, the grain size of Bi1- xCa xFeO3 becomes smaller, showing the role of Ca2+ ions as the dopant for fine grains. The calcination temperatures are the major causes for the saturated magnetization. The residual magnetization ( Mr) and the coercive force ( Hc) decrease linearly with the increase of x value, and due to the effect of Ca2+ substitution at Bi3+ sites, which causes the valence change of Fe and/or the oxygen vacancies. Conclusions: The XRD result indicates that the diffraction peak emerges with the increase of Ca2+ and the main diffraction peak achieves a high angle. The best calcining temperature is 600 °C, and the morphology is very dependent on the calcining temperature.

Synthesis and Photocatalytic Property of FeVO4 Photocatalyst by Sol-Gel Method

2011 ◽  
Vol 328-330 ◽  
pp. 1507-1511 ◽  
Author(s):  
Min Wang ◽  
Li Fang Zhang ◽  
Hai Yan Luan
Keyword(s):  
Photocatalytic Activity ◽  
Citric Acid ◽  
Sol Gel ◽  
Photocatalytic Property ◽  
Molar Ratio ◽  
Halogen Lamp ◽  
Experimental Conditions ◽  
Gel Method ◽  
Sol Gel Method ◽  
Photodegradation Rate

FeVO4 photocatalysts were synthesized by complexing Sol-Gel method using citric acid as chelate and characterized with X-ray diffraction (XRD), scanning electron microsoope(SEM, specific surface area (BET). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under visible light. It was found that the sample prepared with the molar ratio of citric acid to metal inons be 2:1, pH=7 and calcinated under 750°C for 4 hours was pure triclinic FeVO4 phase. In the experimental conditions used, the FeVO4 calcined at 750°C had highest photocatalytic activity with the photodegradation rate was about 85% or so in 150min under 250W halogen lamp.

The Influence of ZnO Components on the Photocatalytic Activity of Fe3O4-CuO-ZnO Nanocomposites

2015 ◽  
Vol 1123 ◽  
pp. 227-232 ◽  
Author(s):  
Iqriah Kalim Susanto ◽  
Ardiansyah Taufik ◽  
Rosari Saleh
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible

Nanocomposite Fe3O4-CuO-ZnO with different molar ratio of Fe3O4:CuO:ZnO were synthesized using sol-gel method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscope, UV-visible diffuse reflectance spectroscopy and vibrating sample magnetometer. The characterization results manifested that the combination of Fe3O4, CuO and ZnO nanoparticles was successful. The photocatalytic activity of nanocomposite with the molar ratio of 1:1:5 was more effective in the degradation of methylene blue under UV light irradiation than pure Fe3O4, CuO, ZnO. The role of photoactive species involved in the photocatalytic reaction was studied and found that holes play the most important role in photodegradation of methylene blue.

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