۱Fabrication of Gas Diffusion Electrodes using Carbon Nanotube–Supported Pt Alloys
اطلاعات انتشار: اولین کنفرانس ملی هیدروژن و پیل سوختی، سال
تعداد صفحات: ۱۰
In this paper, we report the use of Pt binary and ternary alloys prepared by alloying of Pt with transition metals, as catalysts for fabricating of gas diffusion electrodes (GDEs). The electrocatalytic properties for the oxygen reduction reaction (ORR) we<\div>

۲Gas Diffusion Electrodes for Direct Methanol Fuel Cells using Methanol–Resistant Catalyst
اطلاعات انتشار: اولین کنفرانس ملی هیدروژن و پیل سوختی، سال
تعداد صفحات: ۱۲
This work try to solve the problem of methanol cross over through the polymer electrolyte in direct methanol fuel cells (DMFCs) by developing new cathode electrocatalysts with both higher methanol tolerance and higher activity for the oxygen reduction rea<\div>

۳Improve the Catalytic Activity of Pt in GDEs and Comparison of the Acidic and Alkaline Electrolytes
اطلاعات انتشار: اولین کنفرانس ملی هیدروژن و پیل سوختی، سال
تعداد صفحات: ۱۱
The objective of this study is to improve the catalytic activity of platinum by alloying with transition metals (Pd and Cd) in gas diffusion electrodes (GDEs) on oxygen reduction reaction (ORR) at cathode site and comparison of the acidic and alkaline ele<\div>

۴Kinetic Study of Oxygen Reduction Reaction on Platinum Dispersed in Polyaniline Film Electrocatalyst at Various Temperature
اطلاعات انتشار: اولین کنفرانس ملی هیدروژن و پیل سوختی، سال
تعداد صفحات: ۵
The electrochemical reduction of oxygen is the cathode reaction in fuel cells, but kinetically slow. The aim of this work was to study of oxygen reduction at polyaniline modified glassy carbon (GC) electrode at various temperature. Polyaniline deposited a<\div>

۵Kinetic Study of oxygen reduction reaction on platinum particles dispersed in polyaniline film
اطلاعات انتشار: دومین همایش پیل سوختی ایران، سال
تعداد صفحات: ۴
Oxygen reduction reaction is thermodynamically favored but kinetically slow. Oxygen is used in fuel cell systems as oxidant and fuel cell ystem is suitable choice for production of clean energy in the present century. For production of more electricity in these systems, the oxygen reduction reaction must be catalyzed. In order to increase reaction rate, polyaniline was used as a substrate for platinum electrocatalyst. After reaching the optimized conditions, the kinetically parameters for oxygen reduction reaction were studied through the rotating disk electrode voltammetry technique and Tafel plot. At the optimized conditions, the results of Koutecky–Levich analysis indicate that the total number of exchanged electrons, symmetry factor and the electron transfer rate constant, are 2.1e ,0.412,and 10–5.99 cms–1 respectively. Also, the results of Tafel plot analysis show that the exchange current density and the number of the rate–determining step electrons are10–5.13 Acm–2 and 1.03≈1e respectively.<\div>

۶Study of Dielectric Constant effects on preparation conditions of gas diffusion electrodes for Oxygen Reduction Reaction in polymer electrolyte membrane fuel cells
اطلاعات انتشار: دومین همایش پیل سوختی ایران، سال
تعداد صفحات: ۴
The effect of solvent dielectric constant that used for preparation of catalyst layer of gas diffusion electrode (GDE) in Proton exchange membrane fuel cell (PEMFC) cathodes for oxygen reduction was investigated. Electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), Chronoamperometry (CA) and Cyclic Voltammetry (CV) measurements were carried out at 298K in 2.0 M H2SO4 on electrodes with same nafion loading and Pt loading but different solvent dielectric constant for ink preparation. In all electrodes nafion loading of 0.5 mgcm–2 and Pt loading of 1 mgcm–2 were chose. EIS supplied information on the charge transfer resistance and CV on the electrochemical active area for the oxygen reduction reaction (ORR) showed optimum results in states that dielectric constant was 4.2. The results indicate that, under optimized conditions the (solvent dielectric constant of 4.2) exchange current density and Tafel slope are 9.8×10–5mA cm–2 and 66.0 mVdec–1, respectively. Examination of morphology of the prepared electrodes using SEM confirmed that the microstructure of the catalyst layer affected with different solvent dielectric constant.
PEMFC; Gas Diffusion Electrode; Catalyst layer; Oxygen Reduction Reaction; Dielectric Constant.<\div>

۷The 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>

۸Exploration Of Bimetallic Pt–Pd\C Nanoparticles As An Electrocatalyst For Oxygen Reduction Reaction
اطلاعات انتشار: چهاردهمین همایش بین المللی نفت، گاز و پتروشیمی، سال
تعداد صفحات: ۹
in this study carbon supported Pt and Pt–Pd were synthesized as oxygen reduction reaction electrocatalysts in polymer electrolyte membrane fuel cells. Pt and Pt –Pd nanoparticles have been synthesized by reduction of metal precursors with NaBH4. characterization an evaluation the electrocatalysts was carried out by XRD and SEM. electrochemical properties was investigeited by cyclic voltammetry, linear sweep voltammetry, chronoamperometry and impedance electrochemical spectroscopy . the results showed the crystallite size of noble electrocatalysts Pt and Pt–Pd were below 10 nm. also electerochemical studies showed Pt–Pd\C electrocatalyst for oxygen reduction reaction has catalytic activity better than Pt\C.<\div>

۹Platinum 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>

۱۰PdCo 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>

۱۱On the catalytic behavior of copper toward oxygen reduction reaction in alkaline solution
نویسنده(ها): ،
اطلاعات انتشار: انديشه علوم، سال
تعداد صفحات: ۷
در این مقاله جنبه های سینتیکی و مکانیزمی واکنش کاهش اکسیژن و همینطور اثرات الکتروکاتالیتیکی سطح مس به کمک روشهای ولتامتری چرخه‌ای و الکترود دیسک چرخان مورد مطالعه قرار گرفت. در محدوده پتانسیل –0.4 تا –1.4 V\SCE دو پیک وابسته به زمان و یک قسمت صاف در ولتاموگرام های چرخه ای مشاهده گردید. کاهش مستقیم اکسیژن همراه با کاهش اکسیدهای مس که در فواصل زمانی مشخصی که الکترود در پتانسیل مدار باز قرار می گیرد تشکیل می شوند به کمک روشهای الکتروشیمیایی مورد بررسی قرار گرفت. تعداد الکترونهای مبادله شده برای کاهش اکسیژن روی سطح مس در حالتهای مختلف محاسبه و مشاهده گردید که روی سطح مس عاری از اکسید، تعداد الکترون 4 و با رشد لایه اکسیدی روی سطح مس تعداد الکترونها به 2 کاهش می یابد. همچنین، محاسبه ثابتهای سرعت نشان داد که کاهش اکسیژن روی سطح مس عاری از اکسید با سرعت بیشتری انجام می شود. افزایش سطح فعال مس که به خاطر نفوذ و خارج شدن اکسیژن و تخریب و بازسازی مجدد سطح اتفاق می افتد نیز مشاهده گردید

۱۲Borohydride Synthesis of the PtFeCo\Gr Electrocatalysts for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells
اطلاعات انتشار: دومین کنفرانس بین المللی یافته های نوین پژوهشی در شیمی و مهندسی شیمی، سال
تعداد صفحات: ۵
Insufficient catalytic activity and durability are the most challenging issues in the commercialization of proton exchange membrane fuel cells. In an effort to address these barriers, PtFeCo\Gr electrocatalyst were prepared via the reduction of precursors in the presence of glycerol as stabilizer. The electrocatalytic performances of the synthesized PtFeCo\Gr alloy electrocatalysts were compared with that of PtFeCo\Gr electrocatalyst which prepared in the absence of glycerol. Physical property studies (XRD) and electrochemical analyses with catalyst layers immobilized on glassy carbon electrodes and electrochemical behavior of the synthesized electrocatalyst. Finally, a cell performance investigation, using the synthesized electrocatalyst was carried out in a single PEMFC setup.Among these electroctalysts, the PtFeCo\G–A catalyst exhibits the highest activity, a better behavior was obtained for the PtFeCo\G–A and the maximum power density produced from proton exchange membrane fuel cell with PtFeCo\G–A electrocatalyst which was prepared in the presence of glycerol as stabilizer was 9% higher than PtFeCo\G–B which was prepared in the absence of glycerol.<\div>

۱۳Glycerol stabilized Borohydride Synthesis of Supported Pt Alloy Nanoparticles Electrocatalysts for Oxygen Reduction Reaction in PEMFCs
اطلاعات انتشار: دومین کنفرانس بین المللی یافته های نوین پژوهشی در شیمی و مهندسی شیمی، سال
تعداد صفحات: ۶
This paper reports the synthesis of platinum–iron–cobalt alloy nanoparticles dispersed on graphene nanosheets. The particles had large electrochemical surface area. The synthesized electrocatalyst were used in the cathode of a proton membrane exchange fuel cell, in which the maximum power density is 330 mW cm–2 with 0.1 mg cm–2 Pt loading. Electrocatalyst were prepared via the reduction of precursors in the presence of glycerol as stabilizer. The electrocatalytic performances of the synthesized PtFeCo\Gr alloy electrocatalysts were compared with that of PtFeCo\Gr electrocatalyst which prepared in the absence of glycerol. Physical property studies (SEM, TEM micrographs) and electrochemical analyses with catalyst layers immobilized on glassy carbon electrodes (cyclic voltammetry) were carried out to characterize the structural and electrochemical behavior of the synthesized electrocatalyst. Finally, a cell performance investigation, using the synthesized electrocatalyst was carried out in a single PEMFC setup.The electrocatalytic performances of the synthesized electrocatalysts were compared with Pt\Gr by cyclic voltammetry; among these electroctalysts, the catalyst which was prepared in the presence of glycerol as stabilizer exhibits the highest activity and the best stability for oxygen reduction reaction (ORR) in acidic media.<\div>

۱۴Electrochemical Impedance of Oxygen Reduction in Acidic Solution at Silver–Modified Glassy Carbon Electrode
نویسنده(ها): ، ،
اطلاعات انتشار: Analytical & Bioanalytical Electrochemistry، چهارم،شماره۵، Oct ۲۰۱۲، سال
تعداد صفحات: ۱۰
The electro–reduction of oxygen on silver–modified glassy carbon electrode (Ag\GC) in acidic solution at different potentials was studied by ac–impedance spectroscopy. The influence of the electrode potential on impedance of oxygen reduction reaction is studied and a mathematical model was put forward to quantitative account for the impedance behavior of oxygen reduction. At potentials higher than –0.4 V\Ag–AgCl, a pseudo inductive behavior is observed. The conditions required for this behavior are delineated with the use of the impedance model.

۱۵Introducing Pt\ZnO as a new non carbon substrate electro catalyst for oxygen reduction reaction at low temperature acidic fuel cells
نویسنده(ها): ،
اطلاعات انتشار: Iranian Journal of Catalysis، پنجم،شماره۳، ۲۰۱۵، سال
تعداد صفحات: ۹
Gas diffusion electrode was used for providing better conditions in fuel cell systems for oxygen reduction reaction (ORR). Because the slow kinetics of the oxygen reduction reaction at the proton exchange membrane fuel cell cathode restricts fuel cell efficiency. To this end, researchers have used platinum–coated carbon. In the present study, due to the reduction of carbon corrosion, Zinc oxide nanoparticles have been employed as a support material for platinum. The Pt\ZnO nanoparticles catalyst was made via a combined process of impregnation and seeding method. The microstructure of coating was characterized using scanning electron microscopy (SEM) which indicates that Pt nanoparticles are uniformly dispersed on the surface of ZnO. In order to investigate the chemical composition and crystalline phases of coating, X–ray analysis was carried out. Electrochemical Impedance Spectroscopy (EIS) was carried out for comparing the charge transfer effect during the ORR. The catalytic performance of the electrodes for ORR is evaluated through linear sweep voltammetry measurement. The O2 reduction current for Pt\ZnO alone is expectedly low due to the low electronic conductivity in ZnO. However, adding single–wall carbon nanotube (SWCNT) to the reaction layer improves the electrode performance. The prepared Pt\ZnO\SWCNT 30 wt. % electrode shows high catalytic activity for the ORR, which is probably attributed to conductivity changes caused by the addition of SWCNT. The electrochemical active surface area (ECSA) and durability investigation was studied by cyclic voltammetry in nitrogen saturated 0.5 M H2SO4. The results calculated from ECSA measurements were indicated that the degradation rate of optimized electrode is smaller than Pt\C electrode.

۱۶High 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.

۱۷Oxygen reduction reaction on Pt\C at the presence of super paramagnetic of Fe3O4 nanoparticles for PEMFCs
نویسنده(ها): ،
اطلاعات انتشار: Iranian Journal of Hydrogen and Fuel Cell، اول،شماره۱، ۲۰۱۴، سال
تعداد صفحات: ۶
In this paper the role of super paramagnetic iron oxide nanoparticles (SPI) on Platinum nanoclusters on activated carbon (Pt\C) for electrocatalytic oxygen reduction reaction was considered. Four composites of Pt\C and super paramagnetic iron oxide nanoparticles were prepared with the same total composites weight and different loading of Pt\C (1.2, 0.6, 0.4 and 0.3 mg ). The composite attached on a glassy carbon electrode via a thin layer of Nafion, that was made by Nafion solution . The electrochemical tests were carried out by using conventional three electrode system in sulfuric acid electrolyte at room temperature. Cyclic voltammetry, linear sweep voltammetry, rotating disk electrode configuration and chronoamperometry results showed that by decreasing the Pt\C loading, Electroactive surface area and oxygen diffusion coefficient decreased. Also by increasing the Fe3O4 nanoparticles in catalyst composite 2–electron pathway for ORR surpass from 4– electron pathway. Our results showed that in electrode with the same ratio of Pt\C and SPI has the best utilization of Pt for oxygen reduction reaction.

۱۸Single walled carbon nanotube in the reaction layer of gas diffusion electrode for oxygen reduction reaction
اطلاعات انتشار: Iranian Journal of Hydrogen and Fuel Cell، اول،شماره۲، ۲۰۱۴، سال
تعداد صفحات: ۸
In this paper, the effect of surface area of reaction layers in gas diffusion electrodes on oxygen reduction reaction was investigated. For this purpose, various amounts (0.1, 0.2, 0.3, 0.4, 0.5, 1, 1.5 and zero %wt of total loading of reaction layer) of single walled carbon nanotube (SWCNT) were inserted in the reaction layer. The performance of gas diffusion electrodes for oxygen reduction reaction was studied in a three–electrode half–cell system, via linear sweep voltammetry (LSV), cyclic voltammetry (CV), chronoamperometry (CHA) and impedance analysis. The results show that, the existence of SWCNT in the reaction layer improves the exchange current density of ORR, the symmetry factor changed between 0.51 and 0.83, as a whole in the optimized condition (0.4% wt .SWCNT) tendency of gas diffusion electrode for ORR is increased. The addition, influences significantly in electrochemical surface area and the gas diffusion electrode with 0.4%wt SWCNT has lowest charge transfer resistance respect to other electrodes. Our results indicated that the best performance obtains for an electrode with 0.4% single walled carbon nanotube.

۱۹Preparation of Nitrogen–Doped Graphene By Solvothermal Process as Supporting Material for Fuel Cell Catalysts
اطلاعات انتشار: Iranian Journal of Hydrogen and Fuel Cell، اول،شماره۲، ۲۰۱۴، سال
تعداد صفحات: ۷
Development of efficient electrocatalysts for oxygen reduction reaction (ORR) is one of the most important issues for optimizing the performance of fuel cells and metal–air batteries. The introduction of nitrogen into carbon nanostructures has created new pathways for the development of non–precious electrocatalysts in fuel cells. In this work, nitrogen–doped graphene (NG) was synthesized by a low temperature solvothermal process to use as catalyst supports for oxygen reduction reactions (ORR). The morphology of the NG was studied using scanning electron microscopy, transmission electron microscopy and X–ray photoelectron spectroscopy. X–ray photoelectron spectroscopy showed that graphitic (Quaternary), pyridinic and pyridinic oxidized nitrogen formed by designed reaction and these types of nitrogen configurations has been found to be responsible for the ORR catalytic activity of N–doped carbon material. Cyclic voltammetry and linear sweep voltammetry were used to measure electrocatalytic activity. Electrochemical characterization reveal that the produced NG not only as support but also as catalyst has good catalytic activity for oxygen reduction reaction in alkaline media.

۲۰Using the Palladium as core and Platinum as shell for ORR
نویسنده(ها):
اطلاعات انتشار: Iranian Journal of Hydrogen and Fuel Cell، اول،شماره۳، ۲۰۱۴، سال
تعداد صفحات: ۷
In this work, electrocatalyst with core–shell structure (Pd as core and Pt as shell on VulcanXC–72R) was synthesis. Not only this structure can reduce the amount of platinum but it also can increase the gas diffusion electrode (GDE) performance in cathode reaction (Oxygen Reduction Reaction or ORR) of polymer electrolyte membrane fuel cell (PEMFC). To this meaning, one series of electrocatalyst with different molar ratio of metals (Pd @ Pt), was prepared and applied in electrode fabrication. The used synthesis method was impregnation with hydrothermal. The performance of the electrodes in ORR was studied by linear sweep voltametery (LSV), electrochemical impedance spectroscopy (EIS), chronoamperometery techniques and the MEA were also tested. Inductive coupled plasma (ICP), X–ray diffraction (XRD), transmission electron microscopy (TEM) techniques was used to characterize the electrocatalyst. The results indicated that the electrocatalyst with 3:1 molar ratio for Pd: Pt enhanced the cathode in MEA performance. This result can be attributed to the positive effect of Pd, particle size and catalyst distribution on substrate that consequently, provide the best three phase zone.

۲۱Electrodeposition of platinum nanoparticles on reduced graphene oxide as an efficient catalyst for oxygen reduction reaction
نویسنده(ها): ،
اطلاعات انتشار: Iranian Journal of Hydrogen and Fuel Cell، دوم،شماره۱، ۲۰۱۵، سال
تعداد صفحات: ۶
Reduced graphene oxide film was synthesized on a glassy carbon electrode by electro reduction of graphene oxide powders in aqueous solution. Then platinum nano particles were deposited on reduced graphene oxide film that was deposited on the glassy carbon electrode via electro reduction of platinum salt. The Physical morphology of the platinum on reduced graphene oxide film was evaluated by scanning electron microscopy (SEM) and energy dispersive X–ray analysis (EDX). The results showed that, Platinum particles were deposited on reduced graphene oxide film. The performance of Pt on reduced graphene oxide for oxygen reduction reaction was considered with linear sweep voltammetry and electrochemical impedance spectroscopy of catalyst in an acidic solution via three electrode configuration cell. The results showed the proper performance of this green synthesized catalyst for oxygen reduction reaction. so this method for catalyst fabrication is a good candidate for the cathode of proton exchange membrane fuel cells.

۲۲Synthesis of Supported Pt Alloy three Dimensional Rhombus Shapes Nanoparticles for Oxygen Reduction Reaction
اطلاعات انتشار: Iranian Journal of Hydrogen and Fuel Cell، دوم،شماره۲، ۲۰۱۵، سال
تعداد صفحات: ۱۰
In this study PtFeCo ternary alloys nanoparticles of three dimentional (3D) rhombus shapes dispersed on graphene nanosheets (PtFeCo\Gr) were successfully prepared and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer–electrolyte fuel cells. A combination of analytical techniques including powder X–ray diffraction, X–ray photoelectron spectra, inductively coupled plasma–atomic emission spectrometry, scanning electron microscopy and electrochemical methods have been used for characterization of the synthesized electrocatalysts in this study. For comparison, the graphene supported PtFe catalyst (PtFe\Gr), graphene supported PtCo catalyst (PtCo\Gr) binary alloys and graphene supported Pt catalyst (Pt\Gr) were also synthesized and investigated under the same experimental conditions. From the electrochemical analysis, it is found that PtFeCo\Gr particles exhibited an obvious enhancement of ORR activity in comparison with pure Pt and binary alloys. The significantly improved EAS, ORR activity and cell performance is achieved by increasing the utilization of PtCoFe\Gr electrocatalyst by increasing the three–phase boundary in the electrocatalyst layer.

۲۳A NEW GAS DIFFUSION ELECTRODE (GDE) WITH A BETTER O2 REDUCTION ELECTROCATALYSTS WITH VERY LOW PT CONTENTS VIA NANO–SIZED PT–COATED NAFION
نویسنده(ها): ،
اطلاعات انتشار: Journal of Petroleum Science and Technology، سوم،شماره۱، ۲۰۱۳، سال
تعداد صفحات: ۶
In the present study, a new gas diffusion electrode (GDE) (based on Pt\Nafion membrane) is fabricated. The electrochemical results show that the new GDE has the highest electrochemical activity toward the oxygen reduction reaction (ORR) among the three electrodes. The SEM and XRD findings show that a platinum layer can be attached to Nafion membrane closely and firmly with a strong peak corresponding to (111) crystalline face. The results illustrate that placing a Pt monolayer on a Nafion membrane is an attractive way of designing better O2 reduction electrocatalysts with very low Pt contents. Under optimum conditions, Tafel slope, exchange current density (i0), and charge transfer resistance (Rct) are obtained to be respectively equal to 85 mV dec–1, 2×10–3 A, and 8 Ω. For this electrode, the platinum particle size is 4 nm.
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