Cathode Catalysts For Fuel Cells Research Articles

New Manganese Oxide-based Cathode Catalysts for Anion-Exchange Membrane Fuel Cells

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Development of Hybrid Cathode Catalyst for PEM Fuel Cells

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Electrochemical Quartz Crystal Microbalance Analysis of Degradation Reactions of Pt/C Cathode Catalysts for Polymer Electrolyte Fuel Cells

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Development of Ultra-Low Pt Alloy Cathode Catalyst for PEM Fuel Cells

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Fundamental Mechanistic Understanding of Oxygen Reduction on Non-Precious Cathode Catalysts for Fuel Cells

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RDE Study of Oxygen Reduction on Non-Platinum Cathode Catalysts for Alkaline Membrane Fuel Cells

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Synthesis and Electrochemical Performances of LiNiCuZn Oxides as Anode and Cathode Catalyst for Low Temperature Solid Oxide Fuel Cell

Low temperature solid oxide fuel cell (LTSOFC, 300-600 degrees C) is developed with advantages compared to conventional SOFC (800-1000 degrees C). The electrodes with good catalytic activity, high electronic and ionic conductivity are required to achieve high power output. In this work, a LiNiCuZn oxides as anode and cathode catalyst is prepared by slurry method. The structure and morphology of the prepared LiNiCuZn oxides are characterized by X-ray diffraction and field emission scanning electron microscopy. The LiNiCuZn oxides prepared by slurry method are nano Li0.28Ni0.72O, ZnO and CuO compound. The nano-crystallites are congregated to form ball-shape particles with diameter of 800-1000 nm. The LiNiCuZn oxides electrodes exhibits high ion conductivity and low polarization resistance to hydrogen oxidation reaction and oxygen reduction reaction at low temperature. The LTSOFC using the LiNiCuZn oxides electrodes demonstrates good cell performance of 1000 mW cm(-2) when it operates at 470 degrees C. It is considered that nano-composite would be an effective way to develop catalyst for LTSOFC.

Progress of Abiotic Cathode Catalysts for Microbial Fuel Cells

Using oxygen as the electron acceptor in microbial fuel cells(MFC) has many advantages.However,the kinetics of oxygen reduction is rather slow,which may cause the loss of cathode potential.Thereby enhancing the oxygen reduction activity is one of the main focuses of MFC research.The progress of abiotic cathode catalysts of MFC is reviewed in this paper,while the catalytic activities of precious metal Pt,transition metal macrocyclic complexes,and non-noble metallic oxide for oxygen reduction are particularly focused.The transition metal macrocyclic complexes and non-noble metal oxides catalysts display good performances and are expected to become the substitutes for the MFC abiotic cathode Pt catalysts.

Synthesis of conductive rutile-phased Nb0.06Ti0.94O2and its supported Pt electrocatalysts (Pt/Nb0.06Ti0.94O2) for the oxygenreduction reaction

In this paper, Nb-doped TiO(2) with anatase and rutile phases was synthesized by the acid-catalyzed sol-gel method, and used as catalyst supports for the oxygen reduction reaction (ORR). X-ray diffraction (XRD), transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET) were used to characterize the support materials in terms of material structures, morphology, composition, and surface area. XRD analysis showed that both the high concentration of hydrochloric acid present in the synthesis and the presence of Pt in the support could favor the formation of conductive rutile phased TiO(2), resulting in the improvement of electronic conduction of the Nb-doped TiO(2) support, which was confirmed by measured conductivities. For electrochemical characterization and ORR catalyst activity validation, Pt particles were deposited on the supports synthesized in this paper to form several catalysts, which were tested for electrochemical Pt surface area, ORR mass activity and specific activity. A monotonic increase in Pt ORR mass activity with increasing catalyst support's conductivity suggested that the support conductivity plays an important role in enhancing catalyst mass activity. The results showed that these non-carbon supported catalysts are promising as PEM fuel cell cathode catalysts.

Pore Development in Carbonized Hemoglobin by Concurrently Generated MgO Template for Activity Enhancement as Fuel Cell Cathode Catalyst

Various carbon materials with a characteristic morphology and pore structure have been produced using template methods in which a carbon-template composite is once formed and the characteristic features derived from the template are generated after the template removal. In this study, hemoglobin, which is a natural compound that could be abundantly and inexpensively obtained, was used as the carbon material source to produce a carbonaceous noble-metal-free fuel cell cathode catalyst. Magnesium oxide was used as the template concurrently generated with the hemoglobin carbonization from magnesium acetate mixed with hemoglobin as the starting material mixture to enable pore development for improving the activity of the carbonized hemoglobin for the cathodic oxygen reduction. After removal of the MgO template, the substantially developed pores were generated in the carbonized hemoglobin with an amorphous structure observed by total-electron-yield X-ray absorption. The extended X-ray absorption fine structure at the Fe-K edge indicated that Fe was coordinated with four nitrogen atoms (Fe-N(4) moiety) in the carbonized hemoglobin. The oxygen reduction activity of the carbonized hemoglobin evaluated using rotating disk electrodes was dependent on the pore structure. The highly developed pores led to an improved activity.

Development of Ultra-Low Pt Alloy Cathode Catalyst for PEM Fuel Cells

Two approaches are described for the synthesis of ultra-low platinum loading catalysts for polymer electrolyte membrane fuel cell (PEMFC). The first approach is the synthesis of a hybrid cathode catalyst (HCC) which combines a non-platinum carbon based composite catalyst (CCC) with active catalytic sites for oxygen reduction reaction (ORR) as a support and highly active Pt/Pt-alloy catalysts. The activity of HCC is found to be 1.3 times higher than that of Pt/C in the platinum loading range of 0.1-0.4 mg cm-2, while it is 2.6 times that of Pt/C at platinum loading of 0.04 mg cm-2. The goal of our second strategy is the development of activated graphitic carbon (AGC) supported Pt3M1 (M=non-precious transition metal) catalyst (Pt3M1/AGC). The Pt3M1/AGC catalyst showed mass activity of 0.41 A mgPt-1 and specific activity of 1023 µA/cm2 at 0.9 ViR-free. Fuel cell performance evaluation under H2/air exhibited a high current density performance of 1.45 A at 0.56 ViR-free.

Pt Monolayer on Electrodeposited Pd Nanostructures-Advanced Cathode Catalysts for PEM Fuel Cells

The Pt monolayer-shell Pd nanowires/nanorods-core (PtML/PdNW(PdNR)) electrocatalysts, supported on carbon nanoparticles are notable for their very high activity and stable performance towards the oxygen reduction reaction (ORR). In the present work Pd nanostructures are electrochemically deposited on oxidized carbon (COX) surface and the impact of the deposition parameters on the deposits morphology is studied. The electrochemical deposition of Pd nanowires is demonstrated for the first time, and a viable mechanism for the growth of Pd nanostructures is proposed. The one-dimensional growth of the Pd nanowires is ascribed to the hydrogen-underpotential-mediated layer-by-layer deposition of Pd. In addition, the surface structure of deposited nanowires is composed predominantly of {111}-oriented facets that facilitate the enhanced ORR activity and stability of the PtML/PdNW/COX electrocatalysts. The Pt mass and specific activities of these electrocatalysts, as well as their stable performance under potential cycling conditions, are significantly higher than those of the commercial Pt/C electrocatalysts, and highlight their great potential for resolving the remaining obstacles to commercializing PEMFCs.

Preparation and Research of AuNi Cathode Catalyst for Direct Methanol Fuel Cell

AuNi alloy was synthesized by vacuum arc melting in high-purity argon atmosphere. The AuNi alloy was characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The results of EDS indicated that Au and Ni atoms were well-distributed in the alloy. Moreover, the results of XPS exhibited an electronic transfer from Ni to Au in AuNi phase. The Electrocatalytic oxygen reduction reaction (ORR) activity and the methanol tolerance of the AuNi alloy were respectively investigated using the RDE method and the electrochemical cyclic voltammetry. The results suggested that O2was directly oxidized to H2O on the AuNi catalyst via an approximate four-electron reduction pathway, and that the AuNi catalyst had a high electrocatalytic activity for the ORR and an acceptable methanol tolerance, simultaneously.

Copper Nitride Nanocubes: Size-Controlled Synthesis and Application as Cathode Catalyst in Alkaline Fuel Cells

Copper nitride nanocubes are synthesized in a facile one-phase process. The crystal size could be tuned easily by using different primary amines as capping agents. Such Pt-free nanocrystals exhibit electrocatalytic activity toward oxygen reduction and appear to be promising cathodic electrocatalysts in alkaline fuel cells.

Design of Functional Cathode Catalysts for Fuel Cells and Lithium-Air Batteries

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Pt Monolayer on Electrodeposited Pd Nanostructures-Advanced Cathode Catalysts for PEM Fuel Cells

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Development of Ultra-Low Pt Alloy Cathode Catalyst for PEM Fuel Cells

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Non-PGM Cathode Catalysts for Alkaline Membrane Fuel Cells: Enhancement an Optimization

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Various Temperatures Affecting Characteristics of Pt/C Cathode Catalysts for Polymer Electrolyte Membrane Fuel Cells

This study is aimed to increase the activity of cathodic catalysts for PEMFCs(Polymer Electrolyte Membrane Fuel Cells). we investigated the temperature effect of 20wt% Pt/C catalysts at five different temperatures. The catalysts were synthesized by using chemical reduction method. Before adding the formaldehyde as reducing agent, process was undergone for 2 hours at the room temperature (RT), <TEX>$40^{\circ}C$</TEX>, <TEX>$60^{\circ}C$</TEX>, <TEX>$80^{\circ}C$</TEX> and <TEX>$100^{\circ}C$</TEX>, respectively. The performances of synthesize catalysts are compared. The electrochemical oxygen reduction reaction (ORR) was studied on 20wt% Pt/C catalysts by using a glassy carbon electrode through cyclic voltammetric curves (CV) in a 1M H2SO4 solution. The ORR specific activities of 20wt% Pt/C catalysts increased to give a relative ORR catalytic activity ordering of <TEX>$80^{\circ}C$</TEX> > <TEX>$100^{\circ}C$</TEX> > <TEX>$60^{\circ}C$</TEX> > <TEX>$40^{\circ}C$</TEX> > RT. Electrochemical active surface area (EAS) was calculated with cyclic voltammetry analysis. Prepared Pt/C (at <TEX>$80^{\circ}C$</TEX>, <TEX>$100^{\circ}C$</TEX>) catalysts has higher ESA than other catalysts. Physical characterization was made by using X-ray diffraction (XRD) and transmission electron microscope (TEM). The TEM images of the carbon supported platinum electrocatalysts (<TEX>$80^{\circ}C$</TEX>, <TEX>$100^{\circ}C$</TEX>) showed homogenous particle distribution with particle size of about 2~3.5 nm. We found that a higher reaction temperature resulted in more uniform particle distribution than lower reaction temperature and then the XRD results showed that the crystalline structure of the synthesized catalysts are seen FCC structure.

Pore scale modeling of a proton exchange membrane fuel cell catalyst layer: Effects of water vapor and temperature

A pore scale model of a polymer electrolyte membrane (PEM) fuel cell cathode catalyst layer is developed which accounts for species transport, electrochemical reactions and thermal transport. Effective transport parameters are computed over a range of operating conditions including the effective oxygen diffusivity, effective water vapor diffusivity, effective proton conductivity, effective electron conductivity and the effective thermal conductivity. In addition, the total amount of oxygen consumption is computed for different operating conditions. Finally, a critical assessment of the impact of assumptions made in the absence of detailed morphological data is presented.