Showing papers on "Direct methanol fuel cell published in 2010"
TL;DR: Synchrotron based X-ray absorption near-edge structure (XANES) spectroscopy provides unambiguous evidence for the presence of three nitrogen species in graphene oxide with outstanding electrocatalytic activity for methanol oxidation.
Abstract: Heat treatment of graphene oxide (GO) with ammonia flow at various temperatures resulted in different distribution of nitrogen species. Synchrotron based X-ray absorption near-edge structure (XANES) spectroscopy provides unambiguous evidence for the presence of three nitrogen species. The Pt/NG-800 composite exhibits outstanding electrocatalytic activity for methanol oxidation.
388 citations
TL;DR: In this article, the authors present an overview of the development of nanocatalysts for direct methanol fuel cells (DMFCs) and present computational approaches for theoretical modeling of nanomaterials such as carbon nanotubes through molecular dynamic techniques.
248 citations
TL;DR: In this article, a review of the recent advances in hybrid membranes of two main types: Nafion-based and non-Nafion based membranes is presented, which can fulfill all of the essential characteristics to yield the desired performance in DMFCs.
228 citations
TL;DR: In this paper, an overview of electrode structure in general and recent material developments, with particular attention paid to the application of nanotechnology in direct methanol fuel cells (DMFCs), is presented.
132 citations
TL;DR: In this paper, a self-generating template route was developed for preparing the crystalline carbon composed of single-layer, few-layer and multilayer graphene based on coordination and the carburization effect of Fe2+ ions in polyacrylic weak-acid cation-exchanged resin (AC resin).
Abstract: A novel “in situ self-generating template route” is developed for preparing the crystalline carbon composed of single-layer, few-layer, and multilayer graphene based on coordination and the carburization effect of Fe2+ ions in polyacrylic weak-acid cation-exchanged resin (AC resin). The products could be obtained in high-throughput with good crystalline structure. Results showed that the introduction of plentiful Fe2+ into the AC resin framework is crucial to obtain the graphene structure. Specifically, the graphene could not be obtained in the case of either replacing Fe2+ with Fe3+, Co2+, Ni2+ or decreasing the exchange amount of Fe2+ ions. Furthermore, as-prepared graphene could act as an excellent support for Pt catalyst in a direct methanol fuel cell, as demonstrated by higher current and better stability of Pt/graphene catalyst. A rational mechanism of the formation of graphene is proposed on the basic of a series of the experiments.
128 citations
TL;DR: In this paper, the physicochemical and electrochemical properties of the Pt-Ru/CMK-3 catalyst were compared with those of electrocatalysts supported on Vulcan XC-72 and commercial catalyst from E-TEK.
128 citations
TL;DR: In this article, a carbon-supported bimetallic PtmNin electrocatalysts with different Pt/Ni atomic ratios were synthesized through a modified polyol process and characterized by X-ray diffraction, transmission electron microscopy, voltammetry techniques, and single-cell tests.
Abstract: Carbon-supported bimetallic PtmNin electrocatalysts with different Pt/Ni atomic ratios were synthesized through a modified polyol process. The as-prepared electrocatalysts were characterized by X-ray diffraction, transmission electron microscopy, voltammetry techniques, and single-cell tests. It was revealed that the PtmNin bimetallic nanoparticles were uniformly distributed on carbon supports with average diameters of about 3 nm. Pt and Ni were partially alloyed, indicated by the decreased Pt lattice constants compared with that of pure Pt. The results of the electrochemical measurements showed that the PtmNin/C catalysts, compared with the Pt/C, have superior specific activity toward the methanol electrooxidation reaction (MOR) in alkaline media as well as a higher power density in a direct methanol fuel cell test with the Pt3Ni1/C as the anode catalyst. Density functional theory studies further revealed that the electronic structure of Pt was modified by Ni due to the charge transfer from Ni to Pt atom...
127 citations
TL;DR: In this paper, the effects of different operating conditions such as current density and methanol concentration, as well as the addition of a hydrophobic water management layer, on the methenol and water crossover were investigated.
127 citations
TL;DR: In this paper, the quaternized polyvinyl alcohol/alumina (designated as QPVA/Al2O3) nanocomposite polymer membrane was prepared by a solution casting method.
116 citations
TL;DR: In this article, the methanol crossover measurements were performed by measuring crossover current density at an open circuit using humidified nitrogen instead of air at the cathode and applied voltage with a power supply.
108 citations
TL;DR: In this paper, Nafion-carbon (NC) composite membranes were prepared by hydrothermal treatment of nafion membrane impregnated with glucose solution, and the carbon loading of the NC membrane was tuned by controlling the hydro-thermal carbonization time.
Abstract: Nafion-carbon (NC) composite membranes were prepared by hydrothermal treatment of Nafion membrane impregnated with glucose solution. The carbon loading of the NC membrane was tuned by controlling the hydrothermal carbonization time. X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and positron annihilation lifetime spectroscopy were used to characterize plain Nafion and NC composite membranes. Nafion-carbon composite membranes exhibited better proton conductivity and reduced methanol permeability than those of the plain Nafion membrane. A single cell prepared with the NC composite membrane with a carbon loading of 3.6 wt% exhibited the highest cell performance. Compared with the cell performance of plain Nafion membrane, the maximum power density of the new cell improved by 31.7% for an H-2/O-2 fuel cell at room temperature, and by 44.0% for a direct methanol fuel cell at 60 degrees C.
TL;DR: A series of carbon supported bimetallic nanocatalysts (pt-fe/c) with varying pt:fe ratio were prepared by a modified ethylene glycol (eg) method, and then heat-treated under h(2)-ar (10 vol%-h(2)) atmosphere at 900 degrees c as discussed by the authors.
TL;DR: In this article, a comprehensive review of past efforts on the optimization of DMFC systems that operate with concentrated methanol is provided, based on the discussion of the key issues associated with transport of the reactants/products.
TL;DR: In this paper, a PVA/nt-TiO 2 /PSSA composite polymer membrane has been used for air-breathing direct methanol fuel cell, which has excellent electrochemical performance and stands out as a viable candidate for applications in DMFC.
TL;DR: In this paper, polyelectrolyte membranes based on partially sulfonated poly(ether ether ketone) (sPEEK) with various degrees of sulfonation are prepared.
TL;DR: In this article, a simple and ecofriendly procedure based on sol-gel method was used for the preparation of hydroxide conductive organic-inorganic hybrid anion-exchange silica precursor (AESP) with ammonium functionality by ring opening of glycidoxypropyltrimethylammonium chloride under mild heating condition.
TL;DR: In this paper, the effects of the cathode relative humidity, cathode pressure, and oxygen flow rate on the water crossover coefficient, fuel efficiency, and overall performance of the fuel cell were studied.
TL;DR: Veziroglu et al. as discussed by the authors showed that Pt nanoparticles with an average size of 2.6 nm are well uniformly dispersed on porous TiO2, and the electrochemical performance of Pt-TiO2/ITO was evaluated by studying the electrocatalytic oxidation of methanol in an alkaline medium with or without UV illumination.
TL;DR: In this paper, carbon supported Pt-Au nanoparticles with different surface compositions with the dimethylformamide co-reduction method by adjusting the pH value from 14 to 12.
TL;DR: In this paper, a composite of polyaniline nanofibers and Pt/C nano-particles, identified by PANI/Pt/C, was prepared by in-situ electropolymerization of aniline and trifluoromethane sulfonic acid on glassy carbon.
TL;DR: In this article, the performance of methanol electrooxidation performance is dependent on the amount of Nb 2 O 5 loading and the peak current densities of the Nb O 5 (2:2)/C is significantly higher (∼80%) on Pt-Nb 2O5 (2.2) than Pt-Ru(2:1)/C.
Abstract: Nb 2 O 5 incorporated Vulcan carbon XC-72R is prepared by solid-state reaction under intermittent microwave heating (IMH) method and the Pt nanoparticles were dispersed by microwave-assisted polyol process. The electrocatalyst samples were characterized by PXRD, TEM, XPS and the performance for methanol electrooxidation was studied in 0.5 mol L −1 H 2 SO 4 aqueous solutions by cyclic voltammetry, chronopotentiometry and chronoamperometry. The physicochemical characterization reveals that Nb 2 O 5 and Pt nanoparticles were evenly deposited on Vulcan carbon XC-72R. Electrochemical experiments showed that methanol electrooxidation performance is dependent on the amount of Nb 2 O 5 loading and the peak current densities of methanol electrooxidation is significantly higher (∼80%) on Pt–Nb 2 O 5 (2:2)/C than Pt–Ru(2:1)/C. Furthermore, Pt–Nb 2 O 5 (2:2)/C electrocatalyst exhibited slower current decay with time than Pt–Ru(2:1)/C, suggesting good tolerance behavior towards CO-like intermediates. The enhanced electrode response is attributed to the synergistic effect between Pt and Nb 2 O 5 . This work shows that Pt–Nb 2 O 5 /C is a promising anode catalyst for direct methanol fuel cells in terms of its activity and stability towards methanol electrooxidation.
TL;DR: In this article, a two-dimensional, two-phase, non-isothermal model was developed to investigate the water transport characteristics in a passive liquid-feed direct methanol fuel cell (DMFC).
TL;DR: Optical transparent, chemically stable alkaline solid polymer electrolyte membranes were prepared by incorporation KOH in poly(vinyl alcohol) (PVA) and characterized by XRD and SEM-EDX.
TL;DR: In this article, acid base blend membranes have been synthesized by blending sulfonated poly(ether ether ketone) (SPEEK) and various amounts of polysulfone tethered with 5-amino-benzotriazole (a basic polymer).
TL;DR: In this paper, the results of cyclic voltammetry and chronoamperometry demonstrate that the Pt/C catalyst prepared by microwave-assisted polyol process at the pH value of about 12 exhibits the highest catalytic activity for methanol electrooxidation.
TL;DR: In this paper, the influence of the anode and cathode GDL wettability on the current and media distribution was studied using combined in situ high resolution neutron radiography and locally resolved current distribution measurements.
TL;DR: In this article, a proton exchange membrane based on partially sulfonated poly (ether sulfone) (S-PES) with various degrees of sulfonation was synthesized.
TL;DR: PtRuMo/CNTs is a promising anode catalyst for DMFCs, and the appropriate operating conditions of the DMFC with PtRuMo and CNTs as the anode catalysts are MEA activation for 10h, 2.0-2.5
TL;DR: In this paper, the aniline act as a very efficient dispersing agent to debundle CNTs from 200 to 50 nm at a very low concentration of 0.5% in an IPA/water solution.
Abstract: A novel method has been developed to debundle carbon nanotubes (CNTs) and load Pt nanoparticles on them without damaging their graphene structures. In this article, the aniline acts as a very efficient dispersing agent to debundle CNTs from 200 to 50 nm at a very low concentration of 0.5% in an IPA/water solution. The aniline-stabilized CNTs have a larger pore volume and larger amount of mesopores than pristine CNTs, and the debundling of CNTs by aniline appears to be a physical rather than a chemical process. Meanwhile, under the presence of aniline, the Pt nanoparticles are anchored on CNTs with a uniform dispersion and small particle size distribution (1.9 ± 0.4, 2.1 ± 0.3, and 2.4 ± 0.4 nm for 14.9%, 29.1%, and 49.0% Pt/CNT, respectively). It is clear that aniline functions as a dispersant and a stabilizer in this paper. These nanocomposites are applied as electrocatalysts for the cathode of a direct methanol fuel cell. The electrochemical active surface areas of Pt/CNT catalysts are higher than that ...
TL;DR: In this paper, a passive vapor-feed direct methanol fuel cell (DMFC) with a membrane vaporizer and a hydrophobic vapor transport layer (VTL) was investigated experimentally to improve its performance when highly concentrated or neat methanoline was directly used.
Abstract: A passive vapor-feed direct methanol fuel cell (DMFC), which has a membrane vaporizer and a hydrophobic vapor transport layer (VTL), was investigated experimentally to improve its performance when highly concentrated or neat methanol was directly used. DMFCs with different structure parameters, such as the VTL thickness, open area ratio of the vaporizer, and thickness of the water management layer, were tested using different methanol concentrations varying from 6 M to neat methanol. The results showed that the performance of the passive vapor-feed DMFC mainly depended on the trade-off between the methanol vapor supply to the anode and methanol crossover through the membrane. Thickening the VTL, or decreasing the open area ratio of the vaporizer, effectively decreased the transport rate of methanol vapor to the anode, leading to an increase in the concentration of the optimum feeding methanol. The hydrophobic water management layer in the cathode was also useful in lowering the methanol crossover and increasing the membrane hydration level. Through optimizing the structure parameters, a passive vapor-feed DMFC fed with neat methanol, which showed a peak power density of 34 mW cm ―2 and a high fuel efficiency of 62% at room temperature, was developed.