Durability of different carbon nanomaterial supports with PtRu catalyst in a direct methanol fuel cell (original) (raw)
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a b s t r a c t PtRu catalysts with similar particle size and composition were deposited on three different carbon supports: Vulcan, graphitized carbon nanofibers (GNF) and few-walled carbon nanotubes (FWCNT) and their performance for methanol oxidation was studied in an electrochemical cell and in a single cell DMFC. The electrochemical results indicate that with PtRu/GNF and PtRu/FWCNT higher current densities are obtained and oxidation intermediates deactivate the surface less compared to the same catalyst on Vulcan support. Conversely, PtRu/Vulcan provided the highest open circuit voltage OCV and current densities in DMFC experiments due to a well-optimized electrode layer structure.
5 kWe HT-PEFC stack with composite MEA for CHP application
High temperature PEFC Composite Nafion-YSZ MEAs PEMFC stack Flow field a b s t r a c t In this work, the performance of a High Temperature (HT) Polymer Electrolyte Fuel Cell (PEFC) stack for co-generation application was investigated. A 3 kW power unit composed of two 1.5 kW modules was designed, manufactured and tested. The module was composed of 40 composite graphite cell with an active area of 150 cm 2 . Composite Membrane Electrode Assemblies (MEAs) based on Nafion/Zirconia membranes were used to explore the behavior of the stack at high temperature (120 C). Tests were performed in both pure Hydrogen and H 2 /CO 2 /CO mixture at different humidification grade, simulating the exit gas from a methane fuel processor. The fuel cells stack has generated a maximum power of 2400 W at 105 A with pure hydrogen and fully hydrated gases and 1700 W at 90 A by operating at low humidity grade (95/49 RH% for H 2 /Air). In case the stack was fed with reformate simulated stream fully saturated, a maximum power of 2290 W at 105 A was reached: only a power loss of 5% was recorded by using reformate stream instead of pure hydrogen. The humidification grade of Nafion membrane was indicated as the main factor affecting the proton conductivity of Nafion while the addition of the inert compound like YSZ, did not affectthe electrochemical properties of the membrane but, rather has enhanced mechanical resistance at high temperature.
Journal Article 1-Int National J of Hydrogen Energy
Proton exchange membrane fuel cell Sulfonated poly (ether ether keton) Membrane Sulfated zirconia nanoparticles Proton conductivity a b s t r a c t In this study, sulfated zirconia (SZ) nanoparticles were used as inorganic additives in order to improve physicochemical properties of sulfonated poly (ether ether ketone) (SPEEK) membranes especially for fuel cell application at intermediate temperature. Interactive effects of SPEEK sulfonation time and the content of incorporated additive (as the factors) were studied on the proton conductivity and the oxidative stability of the nanocomposite membranes (as the responses) through the response surface method (RSM) using the central composite design (CCD). The optimum parameters were 6.9 h sulfonation time and 5.94 wt. % of sulfated zirconia that represented proton conductivity of 3.88 mS cm À1 (at 100 C and 100% RH) and oxidative stability of 102 min. The sulfonation time had more effect on both responses. Furthermore, the addition of SZ nanoparticles improved both of oxidative stability and proton conductivity. The morphology, thermal and mechanical properties of optimized nanocomposite membrane were investigated by FESEM, TGA, DSC and tensile strength test, respectively. Also, the XRD, TGA, FTIR, EDX and TEM analysis were conducted to characterize the SZ nanoparticles.
International Journal of Hydrogen Energy, 2012
Copolymer Proton conductivity Proton exchange membrane Fuel cell a b s t r a c t A series of Sulfonated Poly (fluorenyl ether ketone) ionomers containing aliphatic functional segments were synthesized and characterized. The monomer 4,4 0 -Dihydroxy-a, u-diphenoxydecane with aliphatic group was conveniently prepared from hydroquinone and 1,10-dibromodecane. A series of sulfonated aliphatic functional groups containing poly-(fluorenyl ether ketone)s with different aliphatic group content were successfully synthesized and characterized in detail, in particular with respect to properties relevant for their application as membrane materials in proton exchange membrane (PEM) fuel cells. Tough and transparent membranes were formed by casting from their solutions. The effects of alkyl groups were investigated by comparison of the PEM properties of the copolymers with different content of aliphatic component on the copolymer chain. The introduction of aliphatic segments can provide an enhanced water uptake, increased proton conductivities, but worse oxidative stability. Transmission electron microscope (TEM) images of j and f revealed an improved phase separation structure under the effect of aliphatic groups. The
Study of thermal conductivity of PEM fuel cell catalyst layers
International Journal of Hydrogen Energy, 2014
Cell (PEMFC) Through-plane thermal conductivity Catalyst layers (CL) Porous transport layer (PTL) Gas diffusion layer (GDL) a b s t r a c t Thermal conductivities and compression of differently composed Polymer Electrolyte Membrane Fuel Cell (PEMFC) Catalyst Layers (CLs) were measured, both when dry and when containing liquid water. The results were compared using a 1-D thermal model.