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  • G. Nikravesh, E. Salehi *, M. Mandooie

    Metal-organic frameworks (MOFs) have emerged as extended-network, highly tunable, crystalline hydrogen storage adsorbents. The uptake of H2 on Zn4O-based MOFs with different linkers was studied in the current work. The binding energies, consecutive binding energy and step energy of H2 adsorption on MOF-177, MOF-200 and a newly defined MOF (named NEW-MOF) have been calculated on different possible sorption sites, using DFT/Dmol3/PBE. The linkers have the same benzene ring in center, but different numbers of phenyl rings, including 3, 6 and 9 phenyl rings in MOF-177, MOF-200 and NEW-MOF around the center ring, respectively. Our study results showed that the binding energy of the H2 molecules with the linker NEW-MOF was -4.165 kcal/mol, more negative than those obtained for MOF-177 (-3.276 kcal/mol) and MOF-200 (-3.438 kcal/mol). The obtained thermo-favorability may be attributed to the less steric hindrance for adsorption of H2 on the MOF with the larger linker. Step energy results showed that the linkers of MOF-177, MOF-200 and NEW-MOF could adsorb 7, 9 and 12 number of H2 molecules, respectively. Results also disclosed adsorbed moles of H2 per 1×1×1 unit cell of the MOFs decreases with increasing the linker length according to the order of 0.263 (for MOF-177), 0.16 (for MOF-200) and 0.137 (for NEW-MOF), mainly due to reduced packing density of the active sites in the MOFs with larger linkers. The most negative binding energy was also tabulated for the perpendicular approaching of H2 molecules to the node of the central phenyl ring with the bonding distance of 3.19 Å from the linker.

    Keywords: Density Function Theory, Metal-Organic Frameworks, Hydrogen Adsorption, Linker Length, Zn4o Cluster
  • Mehrzad Arjmandi, Majid Peyravi *, Mahdi Pourafshari Chenar, Mohsen Jahanshahi, Abolfazl Arjmandi
    To investigate the adsorption property of H2 and CO2 on the organic ligand of C-MOF-5 (H2BDC) and T-MOF-5 (ZnO-doped H2BDC (ZnO-H2BDC)), Density functional theory (DFT) method was performed. First, the adsorption of ZnO on H2BDC resulted in examining binding energies, the charge transfer, density of states, dipole moments and adsorption geometries were investigated. The binding properties have been calculated and investigated theoretically for ZnO-doped H2BDC in terms of binding energies, band structures, Mulliken charges, and density of states (DOSs). According to obtained results, the H2BDC was strongly doped with ZnO. H2 and CO2 adsorption capacities for ZnO-doped H2BDC are significantly enhanced while there are low adsorption capacities for H2BDC. According to results, at least in the organic ligand of the MOF-5, the highest and lowest adsorption of CO2 (or H2) is attributed to the T-MOF-5 and C-MOF-5 respectively. Our calculations reveal that ZnO-doped H2BDC system (T-MOF-5) has much higher adsorption energy and higher net charge transfer value than pristine H2BDC (C-MOF-5). Also by changing in structure from cubic to tetragonal, the main site for H2 and CO2 adsorption was changed.
    Keywords: Adsorption, CO2, DFT, H2, MOF-5, ZnO
  • حجت امراللهی بیوکی*، احمد مشاعی، محمود برهانی زرندی

    در این پژوهش نانوبلورهای چارچوب آلی-فلزی بر پایه یون های فلزی آلومینیوم، بیسموت، کبالت، کروم، مس، قلع، تیتانیوم و روی با ریختار یکنواخت در شرایط حلال گرمایی سنتز شده و به عنوان افزودنی در لایه نشانی TiO2 به عنوان لایه انتقال دهنده الکترون در سلول خورشیدی پروسکایتی استفاده شدند. در اثر بازپخت لایه TiO2 آلاییده با چارچوب آلی-فلزی در محیط هوا، بخش آلی آن حذف شده و ساختار متخلخل TiO2 آلایش یافته به دست آمد. نتایج بررسی ویژگی های نوری و ساختار بلوری لایه متخلخل TiO2 نشان داد که آلایش با چارچوب آلی-فلزی، جذب نوری لایه متخلخل TiO2 در ناحیه مریی-فرابنفش (Uv-Vis) را افزایش و گاف نواری را به کمتر از  eV 7/2 کاهش داده است. بررسی های طیف نورتابی نشان دهنده افزایش انتقال الکترونی و کاهش بازترکیب و در نتیجه افزایش بازدهی تبدیل توان سلول های خورشیدی پروسکایتی، در مقایسه با سلول های تنها برپایه لایه فرو متخلخل (TiO2) است.

    کلید واژگان: اصلاح سطح, بهبود عملکرد فتوولتایی, پروسکایت, چارچوب های نانوساختار آلی-فلزی, سلول خورشیدی
    Amrollahi Bioki *, Moshaii, Borhani Zarandi

    In this research, nanocrystals of metal-organic frameworks (MOF), based on metal ions of aluminum, bismuth, cobalt, chromium, copper, tin, titanium and zinc with homogenous morphology were synthesized using a solvo-thermal method as an organic framework to form the porous MOF-doped TiO2 for electron transport layer in perovskite solar cells. By thermally decomposing the MOF-doped TiO2 layer in air, the organic template was removed, and porous MOF-doped TiO2 was obtained.  The results of optical properties of crystal structure of porous MOF-doped TiO2 layer showed that doping with MOF remarkably improved the absorption ability of TiO2-MOF layer toward the Uv-Vis region with band gap energy less than of 2.7 eV.  The photoluminescence spectroscopy was conducted to illustrate the improvement of electron transfer in the doped material further. The power conversion efficiency of solar cells using MOF-doped TiO2 was found to improve in comparing that of solar cells using pristine mp-TiO2.

    Keywords: Enhancing photovoltaic performance, Nanostructure metal-organic frameworks, Perovskite, Solar cells, Surface modification
  • Kaveh Parvanak Boroujeni *, Somayeh Reiisi, Shahla Hasani Kouchaki
    Pd, Mn3O4 and Ag2MnO4 nanoparticles embedded on Zn-doped Ni-MOF were successfully prepared. The obtained nanostructures (7–20 nm) were well characterized. They were good fluorescent materials. The nanostructures have significant anticancer activity against gastric cancer cells, based on the results of the MTT assay (24 and 48 h) and in this regard Mn3O4/Pd/Zn-Ni-MOF, Ag2MnO4/Pd/Zn-Ni-MOF showed superior effectiveness. The measured IC50 values ranged from 89.41–377.67. The expression of caspase 3, 8 and 9 genes in the treated cells of [Zn-Ni-MOF], 2-PySI@[Zn-Ni-MOF], 2-PySI-Pd@[Zn-Ni-MOF], Mn3O4/Pd/Zn-Ni-MOF, Ag2MnO4/Pd/Zn-Ni-MOF, Mn3O4, and Ag2MnO4 nanostructures was also investigated and multifold increases compared to the control were observed in all cases.
    Keywords: Mofs, Ultrasound-Assisted Synthesis, Gastric Cancer, Cytotoxicity, Nanomaterial
  • Mahshid Zebardast, Abdollah Fallah Shojaei*, Khalil Tabatabaeian
    Metal-organic framework 5 (MOF-5) and bimetallic MOF-5s (Co/Zn and Ni/Zn) were prepared via a simple solvothermal method. Samples were characterized by various techniques such as powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS), inductively coupled plasma (ICP) and elemental analysis (EA). Photocatalytic decolorization of methylene blue (MB) dye in the aqueous solutions was examined under UV and visible light irradiation. The degradation of MB solutions was calculated by changes in the UV–Vis absorbencies of the aqueous solutions at λmax = 664 nm. The influence of various parameters such as the catalyst loading, dye concentration, initial pH of the dye solution and adding electron acceptors (H2O2, tert-Butyl hydroperoxide (TBHP), KBrO3, KIO4 and (NH4)2S2O8) on the degradation reaction was studied. Moreover, metal doping can improve the photocatalytic activity of MOF-5 due to the synergistic effect, narrow band gap and so on. The results show that Co/Zn-MOF-5 photocatalyst exhibited better photocatalytic activity than Ni/Zn-MOF-5 and raw MOF-5 for MB decolorization under UV and visible light irradiation. Furthermore, adding different electron acceptors, except TBHP, enhanced the photocatalytic performance of photocatalysts with a different rate. Also, kinetic studies revealed that the reactions follow pseudo-first-order. Additionally, bimetallic MOF-5s did not show obvious activity reduction in MB decolorization during five recycling usages.
    Keywords: Bimetallic metal-organic frameworks, MOF-5, Photocatalyst, Methylene blue, Electron acceptor
  • Seyed Kamal Blourfrosh, Kazem Mahanpoor *
    In this study, a new and effective catalyst was prepared by supporting the α-Fe2O3 nanoparticles on a metal-organic framework (MOF). The synthesis of nano α-Fe2O3 photocatalyst was performed according to the reflux condensation method. The MOF was synthesized using cadmium nitrate and terephthalic acid. The nano α-Fe2O3 stabilized on the MOF by the solid-state distribution method. The α-Fe2O3/MOF was characterized by FTIR, XRD, SEM, EDX, TEM, N2 adsorption-desorption, and TGA techniques. The α-Fe2O3/MOF was used as a catalyst to the UV/H2O2 photocatalytic decomposition of Cefalexin (CFX) in the aqueous solutions. This process was optimized and modelled using the full factorial experimental design. Initial concentrations of CFX, pH, α- Fe2O3/MOF amounts, and initial concentration of H2O2 were the variables for determining the optimal conditions and mathematical model. The highest decomposition percentage of CFX was 95.84%. The kinetics of this reaction was obtained pseudo-first-order at a constant rate of 0.0769 min-1.
    Keywords: α-Fe2O3, Cefalexin, Metal-organic framework, Photocatalyst, Solid-state distribution
  • shiva salehi, Mustafa Aghazadeh, Isa Karimzadeh

    A Zn-based metal–organic framework (Zn-MOF) was synthesized by a novel electrodeposition method. The prepared Zn-MOF was characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy techniques. The supercapacitive behavior of synthesized MOF was examined using cyclic voltammetry (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS) measurements in 3 M KOH. SEM images confirmed that Zn-MOF is composed of layered cuboid structure properly attached on to nickel foam substrate. Electrochemical behaviors of the Zn-MOF/Ni foam were also evaluated through GCD tests, which showed high specific capacitance of 288 F g–1 at the current density of 2 A g–1. The outcomes showed great potential of fabricated Zn-MOF as a high-performance electrode material for electrochemical supercapacitors.

    Keywords: Electrodeposition, Energy storage, conversion, Metal-Organic-Frameworks, Specific capacitance
  • علی مهدیخانی، حسام فلاح آرانی*، فاطمه دبیر، عارف قنبری

    در این تحقیق تاثیر پراکسید هیدروژن و پراکسید بنزوییل بر ویژگی های ساختاری و خصوصیات سطحی چارچوب فلزی آلی MOF-5و (Zn4O (BDC) 3) مورد بررسی قرار گرفته است. برای این منظور چارچوب فلزی آلی به روش اختلاط مستقیم سنتز شده و در ادامه به منظور بهبود ویژگی های MOF-5 سنتز شده، نسبت های مولی پیش ماده ها نسبت به لیگاند برای به حداقل رساندن خطای محاسبات استوکیومتری و همچنین فرآیند شستشو اصلاح شد. با هدف مشخصه یابی ترکیبات سنتز شده و بررسی اثر پراکسیدها و فرآیند شستشو بر خواص نمونه ها، اندازه گیری های پراش پرتو ایکس، طیف سنجی مادون قرمز با تبدیل فوریه و آنالیز جذب و واجذب نیتروژن انجام گرفت. با توجه به آزمون های انجام شده، نمونه سنتز شده با حضور پراکسید بنزوییل و همچنین با روش شستشو اصلاح شده (DM-P-03) دارای ویژگی های ساختاری، تخلخل، منافذ فعال و مساحت سطح ویژه مطلوب تری در مقایسه با نمونه سنتز شده با پراکسید هیدروژن است. در این نمونه متوسط اندازه بلورک 18/5 نانومتر، سطح ویژه 2307 مترمربع بر گرم، مجموع حجم حفره ها 1/212 سانتی متر مکعب بر گرم و میانگین قطر حفره ها 2/101 نانومتر است. بنابراین نمونه DM-P-03 به عنوان نمونه بهینه انتخاب شده و برای انجام آزمون های ریزساختاری و وزن سنجی-گرماسنجی افتراقی آماده سازی شد. بر اساس تصویر میکروسکوپی الکترونی گسیل میدانی این نمونه از ذرات کوچک شبه کروی نامنظم تشکیل شده و شکل گیری این ریزساختار به حضور پراکسید بنزوییل نسبت داده شده است. با توجه به آنالیز وزن سنجی-گرماسنجی افتراقی ترکیبات روی باقی مانده در نمونه بررسی و پایداری حرارتی ساختار MOF-5 تا دمای 470 درجه سانتی گراد تایید شد.

    کلید واژگان: چارچوب فلزی آلی, 5-MOF, اختلاط مستقیم, پراکسید, فرآیند شستشو, سطح ویژه
    A. Mehdikhani, H. Fallah-Arani *, F. Dabir, A. Ghanbari

    In this research, the effect of hydrogen peroxide (H2O2) and benzoyl peroxide (BPO) on the structural properties, porosity, active pores, and surface area of the MOF-5 (Zn4O(BDC)3) metal-organic framework was studied. For this purpose, the metal-organic framework was synthesized by direct mixing and the molar ratios of the precursors to the ligand were modified to minimize the stoichiometric calculation error as well as the washing process to improve the properties of the synthesized MOF-5. In order to characterize the synthesized compounds and to investigate the effect of peroxides and washing process on the properties of the samples, X-ray diffraction (XRD), fourier Transform infrared spectroscopy (FTIR), and thermogravimetric/Differential scanning calorimetry (TG-DSC) analysis were performed. Structure, pore volume (1.212 cm3/g), and specific surface area (2307 m2/g) were compared to the sample synthesized with H2O2. DM-P-03 was selected as the optimal sample and prepared for thermal stability. According to TG-DSC analysis, the remaining zinc compounds in the sample were checked and the thermal stability of MOF-5 structure was confirmed up to 470°C.

    Keywords: Metal-organic framework, MOF-5, Direct mixing, Peroxide, Washing process, Surface area
  • Xiaomei Ye, Mengmeng Xiong, Kangrui Yuan, Wei Liu, Xiaoqun Cai, Yu Yuan

    In recent years, metal-organic frameworks (MOFs) have gained attention in the biomedical field, particularly as drug carriers for treating tumors. Therefore, we decided to synthesize a novel benzoic acid Zn-based MOF and study the Zn-based MOFs' drug-delivery properties and the drug-delivery system's anticancer effects. This study successfully synthesized a zinc-based MOF using solvent thermal synthesis. The crystal structure of a Zn-based MOF was investigated using thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. Subsequently, the results of UV spectrophotometry showed that Doxorubicin was successfully loaded with a loading amount of 33.74%. Furthermore, the drug release experiments demonstrated that the Zn-based MOF was pH-sensitive, releasing more at a pH of 3.8 than at pH 5.8 or 7.4. Finally, the Zn-based MOF loaded with drugs exhibited high antitumor activity against HepG2 cells while demonstrating remarkably low toxicity to normal cells (LO2). Taken together, these results demonstrate that the Zn-based MOF has the potential to serve as a carrier in the field of drug delivery systems.

    Keywords: Metal-Organic Frameworks, Drug Delivery Systems, Benzoic Acid, Doxorubicin
  • Mojtaba Hadi *, Masoumeh Khonjouki, Hossein Mostaanzadeh, Ali Ehsani
    In this work, the direct electrochemical oxidation of ethylene glycol (EG) on a nickel-based metal-organic framework (MOF)/multiwall carbon nanotubes (CNTs) hybrid composite electrode was investigated. This investigation is used to verify the possibility of using the Ni-MOF/CNTs electrode in the ethylene glycol fuel cells. The morphology of the composite layer on the surface of the electrode substrate was examined by scanning electron microscopy (SEM). The cyclic voltammetry technique was used to examine the typical electrocatalytic performance of the electrode. In 0.1 M NaOH solution, well-defined oxidation and reduction peaks of Ni2+/Ni3+ redox couple were observed. The electrocatalytic current at the Ni-MOF electrode was also studied for comparison with that of the Ni-MOF/CNTs electrode. Owing to the synergetic effect of the MOF and the CNTs, the Ni-MOF/CNTs electrode shows a satisfactory electrocatalytic activity toward the EG electro-oxidation, making it a promising candidate for use as an ideal anode material in direct alkaline alcohol fuel cells.
    Keywords: Metal-Organic Framework, Carbon Nanotube, Fuel Cell, Ethylene Glycol, Electrocatalytic Oxidation
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