توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Increasing the performance of electrode by using the multi–wall carbon nanotube at microporous layer of gas diffusion electrode in polymer exchange membrane fuel cell
اطلاعات انتشار: سومین همایش پیل سوختی ایران، سال
تعداد صفحات: ۶
In this work, the effect of multi–wall carbon nanotubes (MWCNT) at micro porous layer (MPL) on electrode performance was studied. We utilized different percentages of MWCNT and VulcanXC–72R at the MPL of gas–diffusion electrode (GDE) with same Pt loading in the catalyst layer. The performance of the electrodes in Oxygen reduction reaction (ORR) is tested and the structure of MPL is distinguished by different techniques Our results indicate that MWCNT at MPL makes the performance of GDE increases since the following condition exist 80 wt% MWCNT and 20 wt% VulcanXC– 72R with Pt loading 0.5 mg.cm–<\div>

۲Modification of Polyaniline\ Nafion content at PEM Fuel Cells gas diffusion electrodes
اطلاعات انتشار: سومین همایش پیل سوختی ایران، سال
تعداد صفحات: ۱۰
In this work gas diffusion electrodes were fabricated by Nafion and polyaniline (PANI) nanoparticles. The goal of this work was to find the optimal point for the mixing of Nafion and polyaniline in gas diffusion electrodes. The efficiency of electrodes was examined for oxygen reduction reaction and the electrochemical properties of them were investigated by cyclic voltametry, linear sweep voltametry, chronoampermetry and electrochemical impedance spectroscopy. The surface morphology of electrodes were characterized by scanning electron microscope. Results revealed that electrodes including both Nafion and polyaniline work more efficiently compared to electrodes contaning Nafion and polyaniline slightly, but this mixture has optimum point in which electrode performance is maximum.
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۳Platinum based on the vulcan polyaniline doped trifluoromethane sulfonic acid composite as a new electrocatalyst for DMFC
نویسنده(ها): ، ،
اطلاعات انتشار: سومین همایش پیل سوختی ایران، سال
تعداد صفحات: ۱۵
The film of polyaniline nanowires (PANI (NW)) was deposited onto the surface of stainless steel electrode through cyclic voltametry polymerization of aniline (ANI), PANI (NW) was doped with triflorometan sulfonic acid and utilized for the fabrication of Vulcan (C), PANI composite and then Pt particles reduced on (C–PANI) composite, to result a Pt\C– PANI electrocatalyst. , The current peak of methanol oxidation, electrochemical surface area and the stability of Pt\C– PANI is better than Pt\C+ PANI and Pt\C electrodes. –The ionic resistance conductivity of two electrodes which containing polyaniline are rarity smaller than Pt\C and nafion solution catalyst but EIS measurements in modified electrodes don’t show negative impedance after OCV . It is found that the methanol diffusion coefficients in the Pt\C– PANI and Pt\C+ PANI are 2.5 and 2 times higher than the diffusion coefficient of methanol in Pt\C electrode.<\div>

۴The effect of cetyl–trimethylammonium bromide (CTAB) concentration on synthesis of Pt particle size in the reverse micelle
اطلاعات انتشار: سومین همایش پیل سوختی ایران، سال
تعداد صفحات: ۱۷
Synthesis of carbon–supported Pt\C catalysts using a new preparation technique, a water–in–oil microemulsion or reverse micelle method, is reported. The influence of the cetyl–trimethylammonium bromide (CTAB) concentration, as a surfactant, over the reverse micelles size and then over the Pt nanoparticle size was studied. The catalysts were characterized by electrochemical and surface techniques such as: Cyclic voltammetry, chronoamperometry, linear sweep voltammetry impedance spectroscopy, X–ray diffraction and scanning electron microscope. Surface and electrochemical characterizations showed that Pt nanoparticles on catalysts were synthesized since the reverse micelle method was used. The performance of the Pt\C catalysts was tested by the rotating disk electrode and 3–electrode techniques. A trend of catalytic activity for oxygen reduction reaction (ORR) was obtained: Pt\C(CTAB 0.11M) > Pt\C(CTAB 0.22M)> Pt\C(CTAB 0.055M) > Pt\C(CTAB 0.5M) > Pt\C(CTAB 0.022M), showing that Pt\C(CTAB 0.11M) catalyst had a best catalytic activity for ORR.<\div>

۵Knowledge Management and Scientific Information Analysis in IRAN (IRANDOC)
نویسنده(ها):
اطلاعات انتشار: نخستین کنفرانس بین المللی مدیریت سرمایه فکری، سال
تعداد صفحات: ۲۱
Many organizations in the private or public sectors in various parts of the world have started to realize the importance of knowledge management in streamlining their operations. Many organizations in the public sector are knowledge–intensive organizations and poor knowledge management practices might lead to high costs as a result of lost institutional memory, knowledge gaps and poor decisions. This paper discusses the implementation of knowledge management principles and practices in documentation centers. With the increased adoption of information technology and the increasing overall quality and IT competence, documentation centers are well positioned to leverage knowledge management principles and practices to better support their stakeholders with the necessary knowledge to discharge their duties.<\div>

۶Platinum nano particles supported by a Vulcan and conductive polymer substrate as a new Electrocatalyst for PEM
اطلاعات انتشار: چهارمین همایش پیل سوختی ایران، سال
تعداد صفحات: ۱۱
A film of PANI nanowires (PANI (NWs)) was deposited onto the surface of a stainless steel electrode via cyclic voltammetry. During the polymerization of aniline (ANI), PANI( NWs) were doped with trifluoromethane sulfonic acid, and the doped PANI were utilized for the fabrication of a Vulcan (C) PANI composite. Pt particles were subsequently deposited by reduction onto the CPANI composite to produce a Pt\C–PANI electrocatalyst. the electrodes are characterized by cyclic voltammetry, current–potential measurements, electrochemical impedance spectroscopy, and chronoamperometry. The polyaniline is found to be homogenously dispersed in the catalyst layer, making it a good candidate proton and electron conductor. Use of polyaniline instead of Nafion in the catalyst layer, increases the utility of the electrocatalyst by 18%.The results are consistent with the presence of polyaniline as a conductive polymer in the reaction layer reducing the polarization resistance of the electrode in comparison with that of a corresponding electrode containing Nafion. Thus, the present results indicate that PEMFCs using polyaniline–containing electrocatalysts should give superior performance to those using catalysts containing traditional ionomers<\div>

۷PdCo oxygen reduction electrocatalyst for polymer electrolyte membrane and direct methanol fuel cells
اطلاعات انتشار: چهارمین همایش پیل سوختی ایران، سال
تعداد صفحات: ۵
Carbon–supported Pd–Co alloy electrocatalyst were synthesized and characterized for the purpose of the fuel cell cathode oxygen reduction reaction (ORR). An impregnation method was employed for the synthesis, in which EG was used as a reducing agent. The synthesized catalyst was characterized in terms of catalytic activity by electrochemical measurements. Surface cyclic voltammetry was used to confirm the formation of the Pd–Co alloy. In order to improve activity and stability, the catalyst was heat–treated in the temperature of 3000C. The catalyzed ORR kinetics were also studied using the rotating disk electrode (RDE) method. Electrocatalytic ORR activity was also examined in an acidic solution containing methanol. The results showed that the synthesized Pd–Co\C catalyst has methanol tolerant capabilities.<\div>

۸platinum–tin nanoparticles supported by a new vulcan–polyaniline composite as a substitution of PtRu\C in direct methanol fuel cells
اطلاعات انتشار: چهاردهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۵
polyaniline fibers PANI were synthesized by chemical interfacial method and doped with para toluene sulfonic acid . The doped PANI was utilized for the fabrication of a vulcan –poilyaniline composite C–PANI . Pt and sn particles were subsequently deposited by reduction onto the C–PANI composite to produce a ptsn8:2 \C–PANI electrocatalyst .catalytic activity of this electrocatalyst is compared with ptRu\C. cyclic voltamettry studies in methanol oxidation reaction MOR show that the peak current density of ptsn8:2 \C–20%PANI is about 25% more than PtRu\c and its onset potential is about 100mV lesser moreover because of the presence of PANI fibers in catalyst support the methanol diffusion coefficient on this improved catalyst is 2 times more than pt Ru\c.<\div>

۹Investigation of performance of nano particle of platinum coated on carbon support using different methods in single PEM fuel cell
اطلاعات انتشار: اولین همایش بین المللی و ششمین همایش مشترک انجمن مهندسی متالورژی ایران، سال
تعداد صفحات: ۶
Polymer electrolyte membrane fuel cells (PEMFCs) require nano particle platinum (Pt) catalysts to operate effectively at low temperature. In this study, nano particle of platinum coated on carbon support, solvent, and a binder agent were mixed to prepare catalyst ink. The effect of dispersion solvent in catalyst ink performance of the membrane electrode assembly (MEA) for proton exchange membrane fuel cell is studied. Dispersion solvents under examination areWater: IPA and Isooctane: normal butyl acetate with dielectric constant 39.01 and 4.2 respectively. MEAs were prepared by the direct catalyst–coated membrane (CCM) method in which the catalyst layers are coated directly on treated Nafion–115 membrane by spray; MEAs were assembled with gas diffusion electrodes. Electrochemical analyses and physical property examination revealed that the electrode prepared by using mixture of solvent NBA: isooctane with dielectric constant 4.2 showed higher catalyst utilization and better cell performance.<\div>

۱۰High Pt Loading on Polydopamine Functionalized Graphene as a High Performance Cathode Electrocatalyst for Proton Exchange Membrane Fuel Cells
اطلاعات انتشار: Journal of Nano Structures، ششم،شماره۲، ۲۰۱۶، سال
تعداد صفحات: ۱۱
Morphology and size of platinum nanoparticles are a crucial factor in improving their catalytic activity and stability. Here, we firstly report the synthesis of high loading Pt nanoparticles on polydopamine reduced Graphene. The loading concentration of Pt (nanoparticles) NPs on Graphene can be adjusted in the range of 60–70%.With the insertion of polydopamine between Graphene oxide sheets, stacking of Graphene can be effectively prevented, promoting diffusion of oxygen molecules through the Graphene sheets and enhancing the oxygen reduction reaction electrocatalytic activity. Compared to commercial catalysts (i.e., state–of–the–art Pt\C catalyst) the as synthesized Pt supported polydopamine grafted reduced graphite oxide ([email protected]–rGO) hybrid displays very high oxygen reduction reaction catalytic activities. We propose a unique 2D profile of the polydopamine–rGO role as a barrier preventing leaching of Pt into the electrolyte. The fabricated electrodes were evaluated with electrochemical techniques for oxygen reduction reaction and the obtained results were further verified by the transmission electron microscopy micrographs on the microstructure of the integrated [email protected]–rGO structures. It has been revealed that the electrochemical impedance spectroscopy technique can provide more explicit information than polarization curves on the performance dependence on charge–transfer and mass transport processes at different overpotential regions.

۱۱Determination of thermodynamic parameters of hydrogen permeation of palladium membrane for considering the effect of stainless steel support
اطلاعات انتشار: Iranian Journal of Hydrogen and Fuel Cell، اول،شماره۱، ۲۰۱۴، سال
تعداد صفحات: ۱۰
A palladium composite membrane was prepared by electroless plating on oxidized porous stainless steel support (ox–PSS). Hydrogen permeation flux through this composite membrane was measured in the temperature range of 574–674K and the pressure difference of two sides of membrane up to 90kPa. A simplified resistance model was employed to analyze the permeation behavior of hydrogen through Pd\ox–PSS membrane for calculating the contribution of each layer in resistance against the hydrogen transport. The amount of enthalpy of hydrogen dissolution of palladium membrane is –9.4kJ\mol. Considering a complete detailed model, this value was used for discussing the effect of interaction of metal– support on hydrogen exiting from the palladium layer at the downstream side. Several composite membranes which differ in support material has been compared with each other. It was confirmed that the metal–support interaction, plays an effective role in exiting activation energy. In Pd\ox–PSS composite membrane, the metal–support interaction decreases hydrogen exiting rate from Pd membrane’s downstream side.

۱۲One –step synthesis of PdCo alloy nanoparticles decorated on reduced grahene oxide as an Electro–catalyst for Oxygen Reduction Reaction in Passive Direct Methanol Fuel Cells
نویسنده(ها): ، ،
اطلاعات انتشار: Iranian Journal of Hydrogen and Fuel Cell، دوم،شماره۱، ۲۰۱۵، سال
تعداد صفحات: ۷
We report a Pd–Co (3:1)\graphene oxide (Pd3Co \GO) catalyst through a one–step strategy. GO is synthesized from graphite electrodes using ionic liquid–assisted electrochemical exfoliation. Controllable GO–supported Pd3Co electrocatalystis then was reduced by ethylene glycol as a stabilizing agent to prepare highly dispersed PdCo nanoparticles on carbon graphene oxide to be used as oxygen reduction reaction in passive direct methanol fuel cell (DEFC) catalysts. The performance of these electrodes in the ORR was measured with cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), chronoamperometry (CA), inductive coupled plasma (ICP), X–ray diffraction (XRD) and scanning electron microscopy coupled to energy dispersive X–ray (SEM–EDX). Since the Pd3Co\GO alloy electrocatalysts are inactive for the adsorption and oxidation of methanol, it can act as a methanol–tolerant ORR catalyst in a direct methanol fuel cell (DMFC). A membrane–electrode assembly (MEA) has been prepared by employing of the Pd3Co\GO as a cathode for passive direct methanol fuel cell and characterized by polarization curves and impedance diagrams. A better performance was obtained for the cell using Pd3Co\RGO (3.56 mW cm–2) compared to Pd\RGO (1.75 mW cm–2) and Pt\C–Electrochem (1.9 mW cm–2) as cathode in the DMFC.

۱۳Electrooxidations of Ethanol and Acetaldehyde using PtSn\C and PtSnO2\C Catalysts prepared by a Modified Alcohol–reduction Process
اطلاعات انتشار: Scientia Iranica، بيست و دوم،شماره۶، ۲۰۱۵، سال
تعداد صفحات: ۷
Well–dispersed PtSn\C and PtSnO2\C catalysts with anatomic ratio of Pt:Sn (3:1) were deposited onto carbon using a modified alcohol–reduction process for electrochemical oxidation of ethanol. These materials were characterized using energy–dispersive X–ray spectroscopy (EDX) and X–ray diffraction (XRD). An electrochemical study in theethanol and acid medium showed that the PtSnO2\C catalyst had a better performance compared with the PtSn\C and Pt\C catalysts. The CV analysis indicated that the presence of SnO2 increased the sensitivity of the catalyst to oxidation of acetaldehyde because of its low onset potential for the electrooxidation of adsorbed ethanol and acetaldehyde compared to PtSn\C and Pt\C. Since the activation of C–C bond breaking results in the generation of higher current density (mass activity) at higher potentials, the PtSnO2\C catalyst has been found favourable for the overall oxidation of ethanol.
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