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Khatamian M.,Physical Inorganic Chemistry Research Laboratory | Saket Oskoui M.,Physical Inorganic Chemistry Research Laboratory | Haghighi M.,Sahand University of Technology
New Journal of Chemistry | Year: 2014

In this work, we have synthesized CdS quantum dots and also supported CdS nanoparticles on ZSM-5 type metalosilicates (ferrisilicate and aluminosilicate) as CdS-metalosilicate composites. The photocatalytic activity for hydrogen production over the prepared catalysts was investigated. It can be observed that the synthesis of CdS quantum dots by a solvothermal method results in the enhancement of photocatalytic activity of this semiconductor in comparison to other procedures, which has been reported previously. Our objective was to improve the photocatalytic activity of our synthesized CdS nanoparticles; for this purpose, we have supported CdS on metalosilicates and investigated their photocatalytic activity. These composites show high efficiency for hydrogen production under visible light irradiation. This suggests that, due to the high surface area of metalosilicates, the effective and homogenous dispersion of CdS particles on the external surface or within the pores of metalosilicate can be achieved by supporting the nanoparticles which inhibits the agglomeration of the formed semiconductor. We have thus distinguished that supporting of CdS nanoparticles leads to improvement of the photocatalytic activity in water reduction; so that the hydrogen production rate for CdS-metalosilicate composite was about 11 mmol h-1 gcat -1; which is significantly higher than that of unsupported CdS nanoparticles. © 2014 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Khatamian M.,Physical Inorganic Chemistry Research Laboratory | Saket Oskoui M.,Physical Inorganic Chemistry Research Laboratory | Darbandi M.,University of Duisburg - Essen
Microporous and Mesoporous Materials | Year: 2013

Aluminium-free ZSM-5 type chromosilicates as M[Cr]ZSM-5 (M = Na, K and Cs), were synthesized successfully from silicic acid, sodium (or potassium or cesium) carbonate and chromium (III) nitrate using hydrothermal procedure in the presence of tetrapropylammonium bromide (TPABr) as a template. These samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry (TG), Fourier transform infrared spectroscopy (FT-IR) and N2 physical adsorption analysis. The experimental results show that M[Cr]ZSM-5 mesoporous molecular sieves were successfully synthesized. In the synthesis of M[Cr]ZSM-5, a pure MFI phase was obtained with a relatively low concentration of chromium in the synthesis gel. For higher chromium concentration in the synthesis gel, the final product was found to be amorphous. According to N2 physical adsorption analysis, the linear portion of the last section of t-plot, is extrapolated to the adsorption axis of the comparison plot, and this intercept is used to obtain the volume of the micropores. By using different alkalin cations in the synthesis process such as Na or K or Cs, the crystallinity of the zeolite, decreases with the order of Na > K > Cs; studying the porosity characterization of the system with different alkaline cations, also shows the same order for the BET surface area of the samples, but reverse order for the size of pores in the structures of chromosilicates. The effect of various factors, such as crystallization temperature, crystallization time and pH of reaction system on the crystallization process was investigated in detail. © 2013 Elsevier Inc. All rights reserved.

Saket-Oskoui M.,Physical Inorganic Chemistry Research Laboratory | Khatamian M.,Physical Inorganic Chemistry Research Laboratory
Materials Science in Semiconductor Processing | Year: 2014

Titanium dioxide nanoparticles with average particle size of about 5 nm to 60 nm were readily synthesized via a simple, fast and low cost method; polyacrylamide gel method. Furthermore, the effect of the used acid and solvent together with calcination temperature, on crystallite size, morphology, band gaps of resultant material were investigated. The products were characterized by means of thermo gravimetric and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectroscopy analysis. The XRD results show that the presence of different anions in the precursor solution leads to the formation of samples with different anatase/rutile ratios. Their photocatalytic activities were evaluated by photocatalytic degradation of Yellow GX aqueous solution under ultraviolet radiation. The results show that the photocatalyst (TEPC I), containing 79% anatase exhibits the highest photocatalytic activity, which is due to a synergistic effect between anatase and rutile. © 2014 Elsevier Ltd.

Saket-Oskoui M.,Physical Inorganic Chemistry Research Laboratory | Khatamian M.,Physical Inorganic Chemistry Research Laboratory | Nofouzi K.,University of Tabriz | Yavari A.,Physical Inorganic Chemistry Research Laboratory
Advanced Powder Technology | Year: 2014

In this study, polyacrylamide gel method was used for preparation of pure and mixed phase TiO2 nanoparticles. The influence of synthesis conditions on the physicochemical properties of products was investigated. It was found that the type of acid, which was used for acidifying the precursor solution together with calcination temperature can affect the phase structure, crystalline size, morphology and thereby photocatalytic activity of obtained TiO2 nanoparticles. Different trends were observed during the phase transformation, particle growth, shift in energy of band gap with the change in tensile strain to compressive strain of the prepared TiO2 nanomaterial. X-ray diffraction (XRD) showed that prepared nanocrystals, which were calcined at 450 °C have pure anatase and anatase-rutile mixed structures. The prepared samples having crystallite size between 5 nm and 60 nm were observed at different calcination temperatures. In addition, the photocatalytic activities of the prepared samples were evaluated by monitoring the degradation of Cresol Red (CR). The results show that the photocatalyst (TECI), exhibits the highest photocatalytic efficiency where 94.7% of CR can be decomposed after UV exposure for 75 min. © 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Khatamian M.,Physical Inorganic Chemistry Research Laboratory | Khodakarampoor N.,Physical Inorganic Chemistry Research Laboratory | Saket Oskoui M.,Physical Inorganic Chemistry Research Laboratory | Kazemian N.,East Azarbayjan Water and Waste Water Companys Laboratory
RSC Advances | Year: 2015

In this study, composites of Cu-exchanged zeolite/RGO (reduced graphene oxide) with different zeolites (clinoptilolite, ZEA, and ZSM-5) were synthesized. Cu-ZEA/RGO composites with different ratios (namely, 1:1 and 3:1) were also prepared. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses showed that Cu-zeolite/RGO composites were successfully synthesized. The morphologies of the obtained samples were studied by scanning electron microscopy (SEM). Moreover, the Brunauer-Emmett-Teller (BET) technique was used to measure the specific surface area of the samples. The synthesized composites were evaluated as an adsorbent to remove arsenic from contaminated water. According to the results of atomic absorption spectroscopy (AAS), the use of ZEA for preparing the mentioned composite (Cu-exchanged zeolite/RGO) can produce a more efficient performance compared with other zeolites (clinoptilolite and ZSM-5). The Cu-ZEA/RGO composite with 1:1 Cu-ZEA/RGO ratio exhibited the best performance in the removal of arsenic. © 2015 The Royal Society of Chemistry.

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