نتایج جستجو برای: zr mcm 41

تعداد نتایج: 102987  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان - دانشکده مهندسی شیمی و نفت 1391

در پروژه حاضر، ابتدا نانوذرات کروی mcm-41 تهیه شده است. نانوذرات تهیه شده با دارا بودن مساحت سطح ویژه بالا و همچنین خلل و فرج های منظم در ساختار مورد استفاده قرار گرفت. نانوذرات کروی mcm-41 با اصلاح کننده های مناسب اصلاح شد. در تهیه نانوکامپوزیت پلی استایرن از سه نوع نانوذره mcm-41 استفاده شد. محصول گونه اول، نانوذره mcm-41 همراه با استایرن، پراکنشی از نانوذره mcm-41 در ماتریس پلیمری به روش پلی...

Journal: :international journal of nanoscience and nanotechnology 2010
m. masoumi m. r. mehrnia m. m. montazer-rahmati a. m. rashidi

chemical vapor deposition was employed to synthesize carbon nanotubes with ni-loaded mcm-41 and mcm-48 as catalysts and acetylene as precursor at 750°c. mesoporous ni mcm-41 and ni mcm-48 molecular sieves were synthesized by a hydrothermal method and were characterized by xrd and n2 adsorption isotherm. the catalytically synthesized carbon materials were characterized with raman spectroscopy, n...

Journal: :Journal of The Faculty of Engineering and Architecture of Gazi University 2021

Önemli bir hammadde olan izobütene her geçen gün talebin artması, izobütan dehidrojenasyonunu dikkat çekici konuma getirmiştir. Endotermik denge limitasyonlu bu reaksiyon için katalizör sentezi son derece önemlidir. Cr temelli katalizörler monokromatların en aktif tür olduğu bilinmektedir. Bu çalışmada, içeriğinin Cr@MCM-41 yapısına, kromat türleri ve miktarları üzerine etkilerinin araştırılmas...

Journal: :Catalysts 2023

The Ni-based catalyst has been intensively studied for CO methanation. Here, MCM-41 is selected as support to prepare xNi/MCM-41 catalysts with various Ni contents and the catalytic performance methanation in a slurry-bed reactor investigated under different reaction conditions. conversion gradually increases temperature or pressure rises. As content increases, specific surface area pore volume...

F. Farzaneh

Cu(II) complex with L-histidine (His) ligand, immobilized within Al-MCM-41, designated as Cu(His)2/Al-MCM-41 was prepared and characterized by powder X-ray diffraction (XRD), nitrogen adsorption desorption, FTIR, UV-Vis and chemical analysis techniques. The surface area and pore volume were found to decrease after immobilization of Cu(II) complex on Al-MCM-41. It was found that Cu(His)2/Al-MCM-...

Journal: :Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology 2002
Isabel Casades Mercedes Alvaro Hermenegildo García Manoj Narayana Pillai

The influence of the chemical composition and silylation of mesoporous MCM-41 materials on the photochromic behaviour of adsorbed spiropyran (BIPS) and 6-nitrospiropyran was studied. Upon incorporation, the spiropyrans underwent ring opening to form either zwitterionic merocyanine or its corresponding O-protonated form. In all silica MCM-41 or in the MCM-41 containing aluminium, the O-protonate...

2003
Tao Li Soofin Cheng Jyh-Fu Lee Ling-Yun Jang

Molybdenum and zirconium mixed oxides were supported on siliceous MCM-41 mesoporous material. The resultant materials were characterized with various techniques such as X-ray diffraction (XRD), nitrogen adsorption, Transmission electron microscopy (TEM), XANES, NH3-TPD, and Diffuse reflectance infrared Fourier transform spectra (DRIFTS) of pyridine. It was found that the well-ordered channeling...

Journal: :Journal of colloid and interface science 1998
Neimark Ravikovitch Grün Schüth Unger

Methods of nonlocal density functional theory (NLDFT), proposed recently for predictions of adsorption equilibrium and calculations of pore size distributions in micro- and mesoporous materials, were tested on reference MCM-41 materials. Five newly synthesized MCM-41 adsorbents with presumably uniform pore channels varying from 32 to 45 Å were characterized by X-ray diffraction (XRD), nitrogen ...

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