The Characterization and Photocatalytic Properties of Mesoporous WO3•0.33H2O•NiO Nanocrystalline Synthesized through Using the Microwave Radiation Method

2009 ◽  
Vol 60-61 ◽  
pp. 480-485 ◽  
Author(s):  
Li Xia Zou ◽  
Qing Cheng Liu ◽  
Qing Zhong ◽  
Xiu Ming Bai ◽  
Li Jun Dong
Keyword(s):  
Photocatalytic Activity ◽  
Microwave Radiation ◽  
High Surface ◽  
High Surface Area ◽  
Soxhlet Extraction ◽  
Nitrogen Adsorption ◽  
Radiation Method ◽  
Xrd Patterns ◽  
Gaseous Formaldehyde ◽  
Microwave Radiation Method

Mesoporous WO3•0.33H2O was synthesized by the microwave radiation method using surfactant as the template-directing agent, and the template was removed by Soxhlet extraction. The degree of framework substitution had been monitored by means of powder X-ray diffraction (XRD), nitrogen adsorption, and UV-vis diffuse reflectance (DRUV) spectroscopy techniques. Nitrogen adsorption data and XRD patterns confirmed that, the structure, high surface area, and uniform pore size distribution were maintained in the crystallized samples. The photocatalytic activity for the photo-oxidation of gaseous formaldehyde on the mesoporous WO3•0.33H2O synthesized was improved by NiO loading, the photocatalytic activity was higher than both that of the materials synthesized using calcination in high temperature and commercial Degussa P25 TiO2 under visible light and UV irradiation.

scholarly journals Photocatalytic Decolorization of Methyl Red on Nanoporous Anodic ZrO2 of Different Crystal Structures

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 215
Author(s):  
Ewa Wierzbicka ◽  
Karolina Syrek ◽  
Klaudia Mączka ◽  
Grzegorz D. Sulka
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Elevated Temperatures ◽  
Aqueous Electrolyte ◽  
High Surface ◽  
High Surface Area ◽  
Methyl Red ◽  
Self Organized ◽  
Photocatalytic Decolorization ◽  
Perfect Adhesion

High surface area, self-organized nanoporous ZrO2 arrays with perfect adhesion to the Zr substrate were synthesized by anodization in an aqueous electrolyte containing (NH4)2SO4 and NH4F. The obtained semiconductor materials were tested as photocatalysts for decolorization of the methyl red (MR) as a model azo dye pollutant. It was demonstrated that as-synthesized anodic ZrO2 anodic layers are already crystalline and, therefore, do not require further thermal treatment to provide a high photocatalytic performance. However, photocatalytic efficiency could be improved by annealing at a relatively low-temperature of 350 °C. Higher annealing temperatures caused a gradual drop of photocatalytic activity. The photocatalytic behavior was correlated with the crystal phase transformation in anodic ZrO2. It was found that higher photocatalytic activity was observed for the tetragonal phase over the monoclinic phase (predominant at elevated temperatures). It results from the optimal and complex electronic structure of annealed ZrO2 with three different energy states having absorption edges at 2.0, 4.01 and 5.28 eV.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

Facile synthesis and enhanced microwave absorption properties of anthracite-based carbon/Ni3Fe/NiO ternary composites

2020 ◽  
Vol 44 (33) ◽  
pp. 13962-13970
Author(s):  
Hengdong Ren ◽  
Jialin Ma ◽  
Jun Zhou ◽  
Xiangfeng Shu ◽  
Zhenying Liu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Microwave Radiation ◽  
Low Frequency ◽  
Microwave Absorber ◽  
Facile Synthesis ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Radiation Method ◽  
Microwave Radiation Method

A low-frequency microwave absorber was synthesized by using a microwave radiation method.

Cr Doped TiO2 Supported on TUD-1 Photocatalyst for Dye Photodegradation

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Ooi Yee Khai ◽  
Leny Yuliati ◽  
Siew Ling Lee
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Xrd Analysis ◽  
Bandgap Energy ◽  
Doped Tio2 ◽  
Visible Light Driven ◽  
Synthesized Materials

New visible light driven photocatalysts of 1 mol% Cr doped TiO2 supported on TUD-1 have been successfully synthesized. The Cr-TiO2/xTUD-1 (x = 10, 20, 30, 40 and 50) photocatalysts were prepared via surfactant-free sol-gel method followed by wet impregnation procedures. XRD analysis revealed that both TiO2 and Cr were incorporated in the highly porous siliceous matrix. FTIR analysis showed the existence of Si-O-Ti in all the materials. As observed, tetrahedral-coordinated Ti species were dominant in Cr-TiO2/10TUD-1, Cr-TiO2/20TUD-1 and Cr-TiO2/30TUD-1. Meanwhile, octahedral- coordinated Ti species were the dominant species in Cr-TiO2/40TUD-1 and Cr-TiO2/50TUD-1. It has been demonstrated that the amount of TUD-1 as photocatalyst support affected the wavelength response and the bandgap energy of the resulting materials. All the materials have bandgap energy of ~2.9 eV. The photocatalytic performance of the synthesized materials was tested out in dye photodegradation under visible light irradiation at 298 K for 5 hours. Results showed that all Cr-TiO2/TUD-1 materials had higher photocatalytic activity than that of Cr-TiO2. This could be explained by the high surface area and porosity provided by TUD-1 in enhancing the adsorption and diffusivities of the dye molecules, hence leading to the promising photocatalytic activity. Among the materials prepared, Cr-TiO2/30TUD-1 appeared as the most superior photocatalyst which gave the highest dye photodegradation.

High surface area TiO2 nanoparticles: impact of carboxylporphyrin sensitizers in the photocatalytic activity

2020 ◽  
Vol 21 ◽  
pp. 100774
Author(s):  
Caique Prado Machado de Oliveira ◽  
Ana Luísa Almeida Lage ◽  
Dayse Carvalho da Silva Martins ◽  
Nelcy Della Santina Mohallem ◽  
Marcelo Machado Viana
Keyword(s):  
Photocatalytic Activity ◽  
Tio2 Nanoparticles ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area

scholarly journals High performance Ce-doped ZnO nanorods for sunlight-driven photocatalysis

2016 ◽  
Vol 7 ◽  
pp. 1338-1349 ◽  
Author(s):  
Bilel Chouchene ◽  
Tahar Ben Chaabane ◽  
Lavinia Balan ◽  
Emilien Girot ◽  
Kevin Mozet ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Average Length ◽  
High Surface ◽  
Zno Nanorods ◽  
High Surface Area ◽  
Visible Region ◽  
Solar Light ◽  
Effective Electron ◽  
Doped Zno ◽  
Zno Rods

Ce-doped ZnO (ZnO:Ce) nanorods have been prepared through a solvothermal method and the effects of Ce-doping on the structural, optical and electronic properties of ZnO rods were studied. ZnO:Ce rods were characterized by XRD, SEM, TEM, XPS, BET, DRS and Raman spectroscopy. 5% Ce-doped ZnO rods with an average length of 130 nm and a diameter of 23 nm exhibit the highest photocatalytic activity for the degradation of the Orange II dye under solar light irradiation. The high photocatalytic activity is ascribed to the substantially enhanced light absorption in the visible region, to the high surface area of ZnO:Ce rods and to the effective electron–hole pair separation originating from Ce doping. The influence of various experimental parameters like the pH, the presence of salts and of organic compounds was investigated and no marked detrimental effect on the photocatalytic activity was observed. Finally, recyclability experiments demonstrate that ZnO:Ce rods are a stable solar-light photocatalyst.

scholarly journals Synthesis and characterization of porous silica and polyaniline-porous silica composite materials with high surface area

2014 ◽  
Vol 49 (1) ◽  
pp. 1-8
Author(s):  
US Akhtar ◽  
MK Hossain ◽  
MS Miran ◽  
MYA Mollah
Keyword(s):  
Electron Microscopy ◽  
Pore Size ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Porous Silica ◽  
Nitrogen Adsorption ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Cylindrical Pore

Porous silica materials were synthesized from tetraethyl orthosilicate (TEOS) using Pluronic P123 (non-ionic triblock copolymer, EO20PO70O20) as template under acidic conditions which was then used to prepare polyaniline (PAni) and porous silica composites (PAnisilica) at a fixed molar ratio. These materials were characterized by nitrogen adsorption-desorption isotherm measured by Barrett-Joyner- Halenda (BJH) method and pore size distribution from desorption branch and surface area measured by the Brunauer-Emmett-Teller (BET) method, scanning electron microscopy (SEM), transmission electron microscopy (TEM), TEM-energy dispersive X-ray (EDX) and Fourier transform infrared (FT-IR) spectroscopy. The composite maintains its structure even after the polymerization and the polymer is dispersed on the inorganic matrix. The rod-like porous silica was about 1?m to 1.5 ?m long and on an average the diameter was in the range of 300- 500 nm. The SEM and TEM images show well ordered 2d hexagonal pore, high specific surface area (850 m2g-1) and uniform pore size of ca. 6.5 nm in diameter. After incorporation of PAni inside the silica pore, framework of porous silica did not collapse and the surface area of the composite was as high as 434 m2g-1 which was 5.5 time higher than our previous report of 78.3 m2g-1. Due to shrinkage of the framework during the incorporation of aniline inside the silica, the pore diameter slightly increase to 7.5 nm but still showing Type IV isotherm and typical hysteresis loop H1 implying a uniform cylindrical pore geometry. DOI: http://dx.doi.org/10.3329/bjsir.v49i1.18847 Bangladesh J. Sci. Ind. Res. 49(1), 1-8, 2014

Preparation of Mesoporous TiO2 Microspheres by Ultrasonic-Hydrothermal Process and its Photocatalysis

2012 ◽  
Vol 578 ◽  
pp. 99-104
Author(s):  
Yang Lin Liu ◽  
Xue Chen Duan ◽  
Shu Yun Liu ◽  
Yan Yan Liu
Keyword(s):  
Photocatalytic Activity ◽  
Crystal Size ◽  
High Surface ◽  
Hydrothermal Process ◽  
High Surface Area ◽  
Heat Treating ◽  
Mesoporous Tio2 ◽  
Average Crystal Size ◽  
Tio2 Microspheres ◽  
Effects Of Temperature

Mesoporous TiO2 microspheres were prepared by Ultrasonic-Hydrothermal Process with tetrabutyltitanate as titanium resource and octadecylamine as template. The effects of temperature and time of hytrothermol process, and calcination temperature on the structure had been investigated via XRD,SEM,TEM.The results indicated it will be better hythrothermol treating 20h at 120°Cand then heat-treating 4h at 400°C. A high surface area of 261.7 m2/g and pore volume of 0.28cm3/g was obtained in the corresponding sample with quite narrow distribution,and centering at 4.3nm in diameter.TiO2 frame was highly crystallized, showed the characteristic of pure anataste, with average crystal size of 10.0nm. The as-prepared sample possess a morphology of microspheres with diameter about 100-300nm.The photocatalytic activity was valuated by photodegradation of methly orange. The resultes indicated 99.79% of methly orange in the solution was removed after 30min photocatalytic treatment.

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