Comparision of the Preparation Methods of Mesoporous Phosphate Compounds Belonging to NZP Family

2013 ◽  
Vol 631-632 ◽  
pp. 116-120
Author(s):  
Peng Zheng ◽  
Lin Hua Zhu ◽  
Tian Si ◽  
Yan Lin Sun
Keyword(s):  
Pore Diameter ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Powder Materials ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Preparation Methods ◽  
X Ray ◽  
Low Thermal Expansion ◽  
Adsorption Desorption

Using polyethylene oxide (PEO) as template, the new types of mesoporous phosphate compound which belongs to NaZr2(PO4)3(NZP) family were synthesized by copreciptate, sol-gel and mechanochemical activation(MA) route respectively. The physical phase and pore structure of the synthesized powder materials were characterized by X-ray diffraction (XRD) and N2 adsorption–desorption. The results showed that the crystalline NZP family compound with mesoporous structure is formed by sol-gel route followed with calcination as well as MA method followed with hydrothermal treatment when the mole ratio of PEO to Zr is 1:10, and the specific surface area, average pore diameter and pore volume of the synthesized powder is 20-50m2/g, 3-6.nm and 0.05-0.12cm3/g respectively. The above research results indicate that it is promising to expand the application field of the powder of NZP family from low thermal expansion ceramics to catalytic materials.

scholarly journals Photocatalytic activity of Pr-modified TiO2 for the degradation of bisphenol A

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Denise S. Cordeiro ◽  
Fernando L. Cassio ◽  
Larissa Ciccotti ◽  
Thiago L. R. Hewer ◽  
Paola Corio ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Bisphenol A ◽  
Pore Diameter ◽  
Sol Gel ◽  
Bandgap Energy ◽  
Photocatalytic Efficiency ◽  
Average Pore ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Adsorption Desorption

AbstractPraseodymium doped TiO2 nanoparticles were successfully prepared by the sol–gel method and characterized by X-ray powder diffraction, N2 adsorption–desorption isotherm, and UV–vis spectroscopy. The effects of the dopant on the crystallite size, specific surface area, average pore diameter, pore volume, and bandgap energy were investigated. The photocatalytic activity of the catalysts was evaluated by bisphenol A degradation and mineralization, which is a representative endocrine disruptor. Furthermore, under visible light irradiation the Pr-modified TiO2 photocatalysts exhibited higher photocatalytic efficiency than unmodified TiO2. When praseodymium was loaded (1.0–5.0%) onto the surface of TiO2, the rates of degradation and mineralization were increased 3–5 times.

Preparation and Characterization TiO2 Aerogel Fibers

2013 ◽  
Vol 743-744 ◽  
pp. 434-437
Author(s):  
Miao Lv ◽  
Guo Tong Qin ◽  
Wei Wei
Keyword(s):  
Electron Microscopy ◽  
Pore Diameter ◽  
Supercritical Drying ◽  
Mass Ratio ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Adsorption Desorption ◽  
Scanning Electron

TiO2aerogel fibers have been fabricated by electron span combined supercritical drying technique. Polyvinylpyrrolidone (PVP)/TiO2composite fibers are prepared by electrospinning PVP and TiO2precursor Ti (OC4H9)4. TiO2aerogel fibers are obtained by supercritical drying PVP/TiO2composite fibers using ethanol as media. Structural of the aerogel fibers was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and N2adsorption at 77 K. The effect of mass ratio of PVP/TiO2was investigated. SEM shows that pore structure of nanofibers was well developed, with the diameter of nanofibers about 2 μm. N2adsorption/desorption data show that the highest surface area of aerogel fibers reached 241.6 m2/g with the average pore diameter about 10 nm. The aerogel fibers were anatase type TiO2.

Synthesis and Characterization of Co/SBA-15 Catalysts

2016 ◽  
Vol 881 ◽  
pp. 35-40
Author(s):  
Franciele Oliveira Costa ◽  
Carla Gabriela Azevedo Misael ◽  
André Miranda da Silva ◽  
Bianca Viana de Sousa
Keyword(s):  
Molecular Sieve ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Wet Impregnation ◽  
X Ray ◽  
Different Temperatures ◽  
Temperature Programmed

The mesoporous silica SBA-15 molecular sieve has been widely studied due to its unidirectional mesoporous structure, its high average pore diameter, its high thermal and hydrothermal stability and its ability to absorb metal ions, allowing its use as support material for catalysts. This study aimed to synthesize the Co/SBA-15 catalyst, and characterize it through the techniques of X-ray diffraction, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The SBA-15 support was synthesized from the following molar composition of reaction mixture: 1TEOS: 0.017 P123: 5.7 HCl: 173 H2O: 40 EtOH, and after calcined at 550 °C for 6 hours. The Co/SBA-15 catalyst was prepared by incorporating 10% cobalt by wet impregnation. Through the X-ray diffractograms, it was found that the impregnation has not changed the structure of the material. RTP profiles showed the presence of peaks at different temperatures that may be caused by dispersion of the cobalt.

scholarly journals Modification of TiO2 nanoparticles through lanthanum doping and peg templating

2014 ◽  
Vol 8 (4) ◽  
pp. 195-202 ◽  
Author(s):  
Marija Milanovic ◽  
Ljubica Nikolic
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Lanthanum Doping ◽  
X Ray ◽  
Doped Titania ◽  
Adsorption Desorption

Pure and lanthanum doped titania nanopowders were synthesized through a room temperature sol-gel method using a template of polyethylene glycol (PEG). The progress of the synthesis in terms of phase formation and size of nanoparticles was monitored by X-ray diffraction, FTIR spectroscopy and SEM analysis. After calcination at 450?C in air, the results have shown the presence of small particles crystallized predominantly in the form of anatase phase, with significant agglomeration. Nitrogen adsorption-desorption measurements confirmed that all prepared powders are mesoporous with an average pore diameter in range 3.1-3.8 nm. The addition of lanthanum ions leads to the nanopowders with the highest specific surface (BET) area (203m2/g). The obtained powders were compared to TiO2 prepared without a template.

FeYO3@rGO nanocomposites: Synthesis, characterization and application in photooxidative degradation of atrazine under visible light

2021 ◽  
Vol 11 (5) ◽  
pp. 706-716
Author(s):  
Nada D. Al-Khthami ◽  
Tariq Altalhi ◽  
Mohammed Alsawat ◽  
Mohamed S. Amin ◽  
Yousef G. Alghamdi ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Structural Surface ◽  
Adsorption Desorption

Different organic pollutants have been remediated photo catalytically by applying perovskite photocatalysts. Atrazine (ATR) is a pesticide commonly detected as a pollutant in drinking, surface and ground water. Herein, FeYO3@rGO heterojunction was synthesized and applied for photooxidation decomposition of ATR. First, FeYO 3nanoparticles (NPs) were prepared via routine sol-gel. After that, FeYO3 NPs were successfully incorporated with different percentages (5, 10, 15 and 20 wt.%) of reduced graphene oxide (rGO) in the synthesis of novel FeYO3@rGO photocatalyst. Morphological, structural, surface, optoelectrical and optical characteristics of constructed materials were identified via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), adsorption/desorption isotherms, diffusive reflectance (DR) spectra, and photoluminescence response (PL). Furthermore, photocatalytic achievement of the constructed materials was evaluated via photooxidative degradation of ATR. Various investigations affirmed the usefulness of rGO incorporation on the advancement of formed photocatalysts. Actually, novel nanocomposite containing rGO (15 wt.%) possessed diminished bandgap energy, as well as magnified visible light absorption. Furthermore, such nanocomposite presented exceptional photocatalytic achievement when exposed to visible light as ATR was perfectly photooxidized over finite amount (1.6 g · L-1) from the optimized photocatalyst when illuminated for 30 min. The advanced photocatalytic performance of constructed heterojunctions could be accredited mainly to depressed recombination amid induced charges. The constructed FeYO3@rGO nanocomposite is labelled as efficient photocatalyst for remediation of herbicides from aquatic environments.

ZnO-SiO2/Laponite Photocatalyst: Kinetic Study on Photocatalytic Decolorization of Methylene Blue

2014 ◽  
Vol 896 ◽  
pp. 541-544
Author(s):  
Is Fatimah ◽  
N. Nunani Yuyun
Keyword(s):  
Methylene Blue ◽  
Energy Dispersive Spectrometry ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Photocatalytic Decolorization ◽  
Uv Visible ◽  
Gel Preparation ◽  
Adsorption Desorption

ZnO-SiO2/Laponite was prepared by sol-gel preparation procedure consit of SiO2 pillarization to laponite followed by ZnO dispersion by using zinc acetate as precursor. The obtained material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), diffuse reflectance UV-Visible (DRUV-Vis) and N2 adsorption-desorption analysis. The photocatalytic performance of the amterial in methylene blue decolorization was also investigated. Compared with ZnO-SiO2 nanoparticles, it is concluded that ZnO-SiO2/Laponite possess higher photocatalytic activity which obey Temkin isotherm model.

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.

scholarly journals ZnFe2O4-TiO2Nanoparticles within Mesoporous MCM-41

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Aidong Tang ◽  
Yuehua Deng ◽  
Jiao Jin ◽  
Huaming Yang
Keyword(s):  
Sol Gel ◽  
Rutile Phase ◽  
Band Gap Energy ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Agglomeration Of Nanoparticles ◽  
Adsorption Desorption ◽  
Mcm 41

A novel nanocomposite ZnFe2O4-TiO2/MCM-41 (ZTM) was synthesized by a sol-gel method and characterized through X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N2adsorption-desorption, Raman spectroscopy, and ultraviolet visible (UV-vis) spectrophotometry. The results confirmed the incorporation of ZnFe2O4-TiO2nanoparticles inside the pores of the mesoporous MCM-41 host without destroying its integrity. ZnFe2O4nanoparticles can inhibit the transformation of anatase into rutile phase of TiO2. Incorporation of ZnFe2O4-TiO2within MCM-41 avoided the agglomeration of nanoparticles and reduced the band gap energy of TiO2to enhance its visible light photocatalytic activity. UV-vis absorption edges of ZTM nanocomposites redshifted with the increase of Zn/Ti molar ratio. The nanocomposite approach could be a potential choice for enhancing the photoactivity of TiO2, indicating an interesting application in the photodegradation and photoelectric fields.

Effects of mesoporous structure on grain growth of nanostructured tungsten oxide

2004 ◽  
Vol 19 (9) ◽  
pp. 2687-2693 ◽  
Author(s):  
Lay Gaik Teoh ◽  
Jiann Shieh ◽  
Wei Hao Lai ◽  
Min Hsiung Hon
Keyword(s):  
Activation Energy ◽  
Surface Area ◽  
Grain Growth ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
Average Pore ◽  
Transmission Electron ◽  
Show Evidence ◽  
Different Temperatures ◽  
Adsorption Desorption

The effects of mesoporous structure on grain growth were investigated in this study. The synthesis was accomplished using block copolymer as the organic template and tungsten chloride as the inorganic precursor. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy, x-ray diffractometry (XRD), transmission electron microscopy, and N2 adsorption/desorption isotherms were used to characterize the microstructures obtained for different temperatures. TGA and XRD analyses demonstrate that copolymers were expelled at 150–250 °C, and mesoporous structure was stable up to 350 °C. The pore diameter and the surface area evaluated from the Barrett-Joyner-Halenda model and Brunauer–Emmett–Teller method indicated that the average pore diameter is 4.11 nm and specific surface area is 191.5 m2/g for 250 °C calcination. Arrhenius equation used to calculate the activation energy for grain growth demonstrates that the activation energy for grain growth was about 38.1 kJ/mol before mesostructure collapse and 11.3 kJ/mol after collapse. These results show evidence of two different mechanisms governing the process of grain growth. The presence of the pore can be related to the obstacle for grain growth.

Synthesis and Characterization of Polythiophene / SBA-15 Composite

2014 ◽  
Vol 968 ◽  
pp. 49-52
Author(s):  
Qin Qin Hou
Keyword(s):  
Thermogravimetric Analysis ◽  
Oxidative Polymerization ◽  
Mesoporous Structure ◽  
Synthesis And Characterization ◽  
Scan Electron Micrographs ◽  
X Ray Diffraction ◽  
Channel System ◽  
X Ray ◽  
Adsorption Desorption

A new nanocomposite, semiconducting polythiophene (PT) confined in mesoporous silica (SBA-15) was synthesized. PT was formed in the pores of SBA-15 by subsequent oxidative polymerization with FeCl3. Different techniques were used to characterize the nanocomposite formation. X-ray diffraction (XRD) and N2 adsorption/desorption analysis showed that the nanocomposite possesses mesoporous structure, and the residual pore volume of nanocomposite was significantly lower than that of pure empty SBA-15. Scan electron micrographs confirmed the presence of polythiophene inside pore channels of the host, and thermogravimetric analysis proved confinement effect in the channel system.

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