Showing papers on "Direct methanol fuel cell published in 2007"
TL;DR: In this paper, the fabrication of graphitic carbon nitride with 3-dimensional ordered pore arrays is described, and the N-rich porous carbon was utilized for the first time as a support for Pt50-Ru50 alloy catalyst to study the support effect on the anodic performance in direct methanol fuel cells.
Abstract: The fabrication of graphitic carbon nitride with 3-dimensionally extended highly ordered pore arrays is described, and the N-rich porous carbon was utilized for the first time as a support for Pt50–Ru50 alloy catalyst to study the support effect on the anodic performance in direct methanol fuel cells; it displays promising results as a catalyst support in the fuel cell.
299 citations
TL;DR: In this paper, carbon-supported Pd-Co bimetallic nanoparticles were used for the oxygen reduction reaction (ORR) in a direct methanol fuel cell.
191 citations
TL;DR: In this article, a series of the crosslinked sulfonated poly(ether ether ketone) (SPEEK) proton exchange membranes were prepared and the photochemical crosslinking of the SPEEK membranes was carried out by dissolving benzophenone and triethylamine photo-initiator system in the membrane casting solution and then exposing the resulting membranes after solvent evaporation to UV light.
180 citations
TL;DR: In this article, a convectionenhanced serpentine flow field (CESFF) was proposed for polymer electrolyte-based fuel cells, which was obtained by re-patterning conventional single-serpentine flow fields.
164 citations
TL;DR: In this paper, a two-dimensional, isothermal two-phase mass transport model for a liquid-feed direct methanol fuel cell (DMFC) is presented, which is based on the classical multiphase flow in porous media without invoking the assumption of constant gas pressure in unsaturated porous medium flow theory.
148 citations
TL;DR: In this paper, a simple and green method of depositing platinum-based bimetallic nanoparticles (Pt−Ru, Pt−Cu, Pt −Au, Pd, and Pt−Ni) on multiwalled carbon nanotubes (MWCNTs) in supercritical fluid carbon dioxide (sc-CO2) is described.
Abstract: A simple and green method of depositing platinum-based bimetallic nanoparticles (Pt−Ru, Pt−Cu, Pt−Au, Pt−Pd, and Pt−Ni) on multiwalled carbon nanotubes (MWCNTs) in supercritical fluid carbon dioxide (sc-CO2) is described. CO2-soluble metal precursors, such as metal acetylacetonates or hexafluoroacetylacetonates, were used in the experiments. Suitable temperature and pressure conditions for synthesizing each kind of bimetallic nanoparticle are studied. Characterizations of these nanocomposites, performed by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD), all confirmed their presence. These MWCNT-supported bimetallic nanoparticles have average sizes varying from 2.8 to 9.3 nm. The application of these nanocomposites is demonstrated by using them as electrocatalysts for direct methanol fuel cell (DMFC). Their electrochemical activities are studied by using cyclic voltammetry (CV), and their efficiency to oxidize methanol to carbon dioxide is at...
147 citations
TL;DR: In this article, a proton exchange membrane was constructed from sulfonated poly(phthalazinone ether ketone) (sPPEK) and various amounts of sulfonic nanoparticles (silica-SO3H) to compensate for the decrease in ion exchange capacity observed when non-sulfonated nano-fillers are utilized.
147 citations
TL;DR: In this article, the synthesis of PtRu nanoparticles on the multi-walled carbon nanotubes (MWCNTs) by a simple sodium borohydride reduction method was reported.
130 citations
TL;DR: In this article, the feasibility of a high-performance membrane-electrode assembly (MEA) with low electrocatalyst loading on carbon nanotubes (CNTs) grown directly on carbon cloth as an anode was demonstrated.
128 citations
TL;DR: In this article, a 3D structure composed of multiwall carbon nanotubes (MWCNTs) surface decorated with Pt nanoparticles and chitosan (CHI) is prepared by an ice segregation induced self-assembly (ISISA) process.
Abstract: Microchannelled 3D architectures composed of multiwall carbon nanotubes (MWCNTs) surface decorated with Pt nanoparticles and chitosan (CHI) are prepared by an ice segregation induced self-assembly (ISISA) process. The microchannelled structures are highly porous (specific gravity ∼10-2) and exhibit excellent electron conductivity (2.5 S·cm-1) thanks to both the high content of MWCNTs (up to 89 wt %) and their interconnection. The Pt/MWCNT/CHI 3D architectures provide remarkable performance as anodes for a direct methanol fuel cell (DMFC).
127 citations
TL;DR: In this paper, a half-cell consisting of a normal direct methanol fuel cell (DMFC) cathode and a membrane that contacts with an electrolyte solution was developed to investigate the effect of methanoline crossover on the cathode behavior.
TL;DR: Hybrid membranes composed of chitosan (CS) as organic matrix and surface modified Y zeolite as inorganic filler are prepared and their applicability for DMFC is demonstrated by methanol permeability, proton conductivity and swelling property.
TL;DR: In this paper, the effects of cell conditioning, temperature, fuel concentration, and Nafion® thickness on the rate of formic acid crossover were examined and compared with methanol crossover.
TL;DR: In this article, the anodic Pt-Ru-Ni/C and the Pt−Ru/C catalysts for potential application in direct methanol fuel cell (DMFC) were prepared by chemical reduction method.
TL;DR: In this paper, SPS-Si composite phosphorylated membrane with 20% silica content (SPSSi(P)/20) was used for direct methanol fuel cell applications.
TL;DR: In this paper, the authors measured the carbon dioxide concentration at the cathode exit in real-time and analyzed the relationship between methanol crossover and cell current density to find the optimal operating conditions.
TL;DR: In this article, the physicochemical properties of polyaniline and silica modified Nation membranes were investigated by means of X-ray diffraction and Fourier transform infrared techniques.
TL;DR: In this paper, a novel chemical strategy is described for the preparation and characterization of carbon-supported and Pt-modified Au nanoparticles, which were prepared by using a successive reduction process.
TL;DR: In this paper, transition metal oxides (ZrO 2, TiO 2, SnO 2 and Nb 2 O 5 ) made by sputtering methods were investigated as new electrocatalysts for the cathode of a direct methanol fuel cell (DMFC) without platinum.
Abstract: Transition metal oxides (ZrO 2 , TiO 2 , SnO 2 , Nb 2 O 5 , and Co 3 O 4 ) made by sputtering methods were investigated as new electrocatalysts for the cathode of a direct methanol fuel cell (DMFC) without platinum. The catalytic activity for the oxygen reduction of these transition metal oxides was evaluated in sulfuric acid with and without 0.1 M methanol. The sputtered metal oxides had stable states in acid medium at least in the potential range of the oxygen reduction. The metal oxides were not active for the methanol oxidation. The oxygen reduction activity of the metal oxides decreased in the following order: ZrO 2-x > Co 3 O 4-x > TiO 2-x ≈ SnO 2-x > Nb 2 O 5-x in the presence of methanol. Zirconium oxides showed the best activity for the oxygen reduction among these transition metal oxides. Moreover, in comparison with the sputtered Pt, the potential at i O2-N2 = -5 μA cm -2 of ZrO 2-x was 60 mV larger than that of the sputtered Pt. This is due to the high selectivity of the metal oxides for the oxygen reduction. The mixed potential as found on the Pt electrode was not observed on the metal oxide catalysts. Zirconium oxides could be a good cathode substituting the platinum cathode for DMFCs.
TL;DR: In this paper, sulfonated poly(arylene ether sulfone) (SPAES) and hydrophilic fumed silica (SiO2) were used as a polymer matrix and an inorganic nanoparticle, respectively.
TL;DR: In this paper, a new membrane electrode assembly (MEA) was proposed, in which the conventional cathode gas diffusion layer (GDL) is eliminated while utilizing a porous metal structure for transporting oxygen and collecting current.
TL;DR: In this article, water and air management systems were developed for a miniature, passive direct methanol fuel cell (DMFC), and the membrane thickness, water management system, air management system and gas diffusion electrodes (GDE) were examined to find their effects on the water balance coefficient, fuel utilization efficiency, energy efficiency and power density.
TL;DR: Partially fluorinated disulfonated poly(arylene ether benzonitrile) random or statistical copolymers were synthesized by direct nucleophilic substitution copolymerization reactions.
TL;DR: In this paper, a carbon aerogel (CA) loaded with platinum nanoparticles can achieve good catalytic performance in proton exchange membrane fuel cells through a simple process and achieved good cell performance when used as a direct methanol fuel cell anode catalyst.
TL;DR: In this paper, a three-dimensional (3D), two-phase model for direct methanol fuel cell (DMFC) is presented, in particular considering water transport and treating the catalyst layer explicitly as a component.
Abstract: Recent research indicates that performance and design of a liquid feed direct methanol fuel cell (DMFC) is controlled not only by electrochemical kinetics and methanol crossover but also by water transport and by their complex interactions in the design regime for portable electronics applications. In this paper, a three-dimensional (3D), two-phase model is presented for DMFCs, in particular considering water transport and treating the catalyst layer explicitly as a component rather than an interface without thickness. Other features of the model are similar to an earlier version published in 2003. The DMFC model is based on the multiphase mixture formulation and encompasses all components in a DMFC using a single computational domain. A flow solver, Fluent, is employed to simultaneously solve flow, species, and charge-transport equations. Numerical simulations in 3D are carried out to explore mass transport phenomena occurring in DMFCs for portable applications as well as to reveal an interplay between the local current density and methanol crossover rate. Numerical results also indicate that the anode flow field design and methanol feeding concentration are two key parameters for optimal cell performance.
TL;DR: In this article, a series of composite membranes based on zeolite A and Nafion 117 have been fabricated for direct methanol fuel cells, where the external surface of the membrane has been modified to enhance the interface bonding between inorganic zeolites and NaA ionomer.
15 Jul 2007-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, sulfonated poly(ether ether ketone) (SPEEK) membranes with various degrees of sulfonation (DS) have been prepared as a potential membrane material for proton exchange membrane by sulfonization process using mixtures of (15−30% concentration) fuming sulfuric acid and (95−98%) concentrated sulfuric acids as the sulfonating agent.
Abstract: Sulfonated poly(ether ether ketone) (SPEEK) membranes with various degrees of sulfonation (DS) have been prepared as a potential membrane material for proton exchange membrane by sulfonation process using mixtures of (15–30% concentration) fuming sulfuric acid and (95–98%) concentrated sulfuric acid as the sulfonating agent. The sulfonation process was conducted at room temperature by varying the acid ratio and reaction time. The produced membranes were then characterized by evaluating the ion exchange capacity (IEC), water uptake, thermal stability, proton conductivity and methanol permeability as a function of degree of sulfonation. The proton conductivity of the sulfonated PEEK membranes with various DS was within the magnitude of 10−3 and 10−2 S cm−1 at room temperature and the methanol permeability was in the range of 3.45 × 10−7 to 2.73 × 10−6 cm2 s−1. The overall membrane performance of the SPEEK membrane with 80% DS was six times higher than Nafion membrane. In conclusion, the SPEEK membrane produced was acceptable and stable enough within the temperature range of direct methanol fuel cell (DMFC) application.
TL;DR: In this article, a series of parametric studies were carried out to evaluate the effects on the CO2 gas bubbles dynamics as well as the cell performance of a 9 cm2 transparent direct methanol fuel cell.