The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform

Kiencuong Pham - One of the best experts on this subject based on the ideXlab platform.

  • graphene carbon nanotube hybrids as robust Catalyst supports in proton exchange membrane fuel cells
    Journal of The Electrochemical Society, 2016
    Co-Authors: Kiencuong Pham, David S Mcphail, Cecilia Mattevi, A T S Wee, Daniel H C Chua
    Abstract:

    Catalyst degradation is one major challenge preventing the worldwide commercialization of the Proton Exchange Membrane Fuel Cells. In this study, we investigate the development of a novel hierarchical carbonaceous support for the Platinum Catalysts, called graphene-carbon nanotube hybrids (GCNT), and its degradation behavior during an accelerated degradation test. The carbon support is fabricated by growing graphene directly onto carbon nanotubes to form a unique all-carbon nanostructure possessing both an ultra-high density of exposed graphitic edges of graphene and a porous structure of carbon nanotubes. The GCNT-supported Platinum Catalyst exhibits a higher intrinsic catalytic activity than a carbon black-supported Platinum Catalyst, and much higher than a CNT-supported Platinum Catalyst. The enhanced catalytic activity of the GCNT-supported Platinum Catalyst is explained by the high graphitic edge density which promotes the catalytic reactions on Platinum Catalyst. The GCNT-supported Platinum Catalyst also exhibits a superior electrochemical stability over that of the carbon black-supported Platinum Catalyst, explained by the high crystallinity of the GCNT support. The superior stability is expressed by a lower loss in polarization performance, a smaller increase in charge transfer resistance, a lower loss in the Platinum electrochemical surface area, a lower rate of carbon corrosion, and a more

N R K Vilambi - One of the best experts on this subject based on the ideXlab platform.

  • preparation of high Platinum utilization gas diffusion electrodes for proton exchange membrane fuel cells
    Journal of The Electrochemical Society, 1992
    Co-Authors: E. J. Taylor, Everett B Anderson, N R K Vilambi
    Abstract:

    We evaluated an electrochemical catalyzation technique for producing gas-diffusion electrodes for proton-exchange-membrane fuel cells (PEMFC). The electrochemical technique deposits Platinum Catalyst particles in regions of the electrode that are in ionic contact with the proton-exchange membrane and in electronic contact with the carbon support. Since ionic and electronic contact the amount of Platinum required for PEMFC. We present data for oxygen reduction and hydrogen oxidation with gas-diffusion electrodes containing 0.05 mg Pt/cm 2

Xianguo Li - One of the best experts on this subject based on the ideXlab platform.

  • composition and performance modelling of Catalyst layer in a proton exchange membrane fuel cell
    Journal of Power Sources, 1999
    Co-Authors: Curtis Marr, Xianguo Li
    Abstract:

    The composition and performance optimisation of cathode Catalyst Platinum and Catalyst layer structure in a proton exchange membrane fuel cell has been investigated by including both electrochemical reaction and mass transport process. It is found that electrochemical reactions occur in a thin layer within a few micrometers thick, indicating ineffective Catalyst utilization for the present Catalyst layer design. The effective use of Platinum Catalyst decreases with increasing current density, hence lower loadings of Platinum are feasible for higher current densities of practical interest without adverse effect on cell performance. The optimal void fraction for the Catalyst layer is about 60% and fairly independent of current density, and a 40% supported Platinum Catalyst yields the best performance amongst various supported Catalysts investigated. An optimal amount of membrane content in the void region of the Catalyst layer exists for minimum cathode voltage losses due to competition between proton migration through the membrane and oxygen transfer in the void region. The present results will be useful for practical fuel cell designs.

Eivind Morten Skou - One of the best experts on this subject based on the ideXlab platform.

  • durability of carbon nanofiber cnf carbon nanotube cnt as Catalyst support for proton exchange membrane fuel cells
    Solid State Ionics, 2013
    Co-Authors: Shuang Ma Andersen, Maryam Borghei, P Lund, Ylirantala Elina, Antti T Pasanen, Esko I Kauppinen, Virginia Ruiz, Pertti Kauranen, Eivind Morten Skou
    Abstract:

    Abstract Durability issues have recently been given much attention in Proton Exchange Membrane Fuel Cell (PEMFC) research. It gives fundamental definition for cell life time, capital cost, system stability and technique reliability. Loss of Catalyst surface area due to corrosion of supporting material (normally carbon black) is one of the essential degradation mechanisms during cell operation. In this work, durability of carbon nanofibers (CNF) & carbon nanotubes (CNT) as alternative Platinum Catalyst supports for Proton Exchange Membrane Fuel Cells (PEMFCs) was assessed. Platinized CNF and CNT using a standard polyol method were prepared and fabricated as cathodes of Membrane Electrode Assemblies (MEA) for PEMFC. Both the Catalysts as such and the MEAs made out of them were evaluated regarding to thermal and electrochemical stabilities using traditional carbon black (Vulcan XC72) as a reference. Thermal gravimetric analysis (TGA), cyclic voltammetry (CV), polarization curve and impedance spectroscopy were applied on the samples under accelerated stress conditions. The carbon nano-materials demonstrated better stability as a support for nano-sized Platinum Catalyst under PEMFC related operating conditions. Due to different morphology of the nano carbons compared to Vulcan XC 72 the electrode structures may still need optimization to improve the overall cell performance.

Daniel H C Chua - One of the best experts on this subject based on the ideXlab platform.

  • graphene carbon nanotube hybrids as robust Catalyst supports in proton exchange membrane fuel cells
    Journal of The Electrochemical Society, 2016
    Co-Authors: Kiencuong Pham, David S Mcphail, Cecilia Mattevi, A T S Wee, Daniel H C Chua
    Abstract:

    Catalyst degradation is one major challenge preventing the worldwide commercialization of the Proton Exchange Membrane Fuel Cells. In this study, we investigate the development of a novel hierarchical carbonaceous support for the Platinum Catalysts, called graphene-carbon nanotube hybrids (GCNT), and its degradation behavior during an accelerated degradation test. The carbon support is fabricated by growing graphene directly onto carbon nanotubes to form a unique all-carbon nanostructure possessing both an ultra-high density of exposed graphitic edges of graphene and a porous structure of carbon nanotubes. The GCNT-supported Platinum Catalyst exhibits a higher intrinsic catalytic activity than a carbon black-supported Platinum Catalyst, and much higher than a CNT-supported Platinum Catalyst. The enhanced catalytic activity of the GCNT-supported Platinum Catalyst is explained by the high graphitic edge density which promotes the catalytic reactions on Platinum Catalyst. The GCNT-supported Platinum Catalyst also exhibits a superior electrochemical stability over that of the carbon black-supported Platinum Catalyst, explained by the high crystallinity of the GCNT support. The superior stability is expressed by a lower loss in polarization performance, a smaller increase in charge transfer resistance, a lower loss in the Platinum electrochemical surface area, a lower rate of carbon corrosion, and a more