Functionalized titania nanotube composite membranes for high temperature proton exchange membrane fuel cells

International Journal of Hydrogen Energy 03/2011; 36(10):6073-6081. DOI: 10.1016/j.ijhydene.2011.02.030

ABSTRACT In this study, functionalized titania nanotubes (F-TiO2-NT) were synthesized by using 3- mercaptopropyl-tri-methoxysilane (MPTMS) as a sulfonic acid functionalization agent. These F-TiO2-NT were investigated for potential application in high temperature hydrogen polymer electrolyte membrane fuel cells (PEMFCs), specifically as an additive to the proton exchange membrane. Fourier transform infrared spectroscopy (FT-IR) and X-ray photo- electron spectroscopy (XPS) results confirmed that the sulfonic acid groups were successfully grafted onto the titania nanotubes (TiO2-NT). F-TiO2-NT showed a much higher conductivity than non-functionalized titania nanotubes. At 80 C, the conductivity of F-TiO2-NT was 0.08 S/cm, superior to that of 0.0011 S/cm for the non-functionalized TiO2-NT. The F-TiO2-NT/Nafion composite membrane shows good proton conductivity at high temperature and low humidity, where at 120 C and 30% relative humidity, the proton conductivity of the composite membrane is 0.067 S/cm, a great improvement over 0.012 S/cm for a recast Nafion membrane. Based on the results of this study, F-TiO2-NT has great potential for membrane applications in high temperature PEMFCs.

Download full-text


Available from: Zhongwei Chen, Jul 24, 2014
80 Reads
  • Source
    • "Particularly, the great water retention ability induced by large specific surface as well as capillary effect and the moderate proton conductivity of titanate nanotube itself makes it suitable as hygroscopic additives in polymer electrolyte membrane for elevated temperature fuel cell applications [20] [21] [22] [23] [24]. For example, Matos et al. have observed the power density of about 0.72 W cm À 2 at 130 1C with fully humidification of gas under a system pressure of 3 bar using the membrane containing 5 wt% of titanate nanotube [22]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Amine-tailored titanate nanotube is introduced to polymer electrolyte membranes for improving the interfacial compatibility between polymeric resin and inorganic materials and enhancing the proton conductivity of the membrane at low relative humidity. Amine-tailored titanate nanotubes are formed through the coupling reaction of surface hydroxyl groups with 3-aminopropyltrimethoxysilane in anhydrous toluene. The grafting density of surface-tailored amino groups reaches 5.19×10−3 mol g−1. Vibrational spectroscopy and X-ray photoelectron spectroscopy confirm that both hydrogen-bonded and free amino groups exist on surface functionalized titanate nanotubes. Polymer electrolyte composite membranes containing the surface functionalized titanate nanotubes and Nafion polymers are characterized for the interfacial compatibility and proton conductivity. The surface grafted amino-groups exhibit positive effect on the interfacial compatibility of polymeric materials and inorganic materials, resulting in increased yield strength of composite membranes. At 100° C and 50% relative humidity, the proton conductivity of the formed composite membrane impregnated with functionalized titanate nanotubes reaches 0.045 Scm−1 that is about 4–5 times higher than that of pristine Nafion membrane and 3 times higher than that of composite membrane impregnated with unmodified titanate nanotubes.
    Journal of Membrane Science 12/2012; s 423–424:284–292. DOI:10.1016/j.memsci.2012.08.025 · 5.06 Impact Factor
  • Source
    • "Composite perfluorosulfonic membranes based on Nafion containing hygroscopic ceramic oxides (such as titania nanotubes [4] and particles [5] [6], Zr(HPO 4 ) 2 [7] [8], ZrO 2 [9], Fe 2 O 3 [10], SiO 2 [11e14], etc) have been demonstrated to operate up to about 150 C both in direct methanol [15] and hydrogeneair [14] [16] [17] polymer electrolyte fuel cells with reduced preheating temperature for the reactants (85 C). As opposite, Nafion membranes without ceramic fillers may operate only up to 130 C [2] under elevated pressures (4 atm abs) and with higher reactants preheating temperature (120e140 C). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Synthetic and natural smectite clays, with different structural and physical parameters, were tested as nanofillers for the creation of Nafion nanocomposites. The solution intercalation method has been successfully applied for incorporation of layered materials into the polymer, while the effect of the solvent, temperature and filler loading were examined in order to determine the optimum conditions for the preparation of highly homogeneous composites.NMR methods, including pulsed-field-gradient spin-echo (PFGSE) and spin-lattice relaxation time (T1) were used to investigate behavior of water confined in recast Nafion and in Nafion–clay hybrids membranes.The transport mechanism appears to be influenced from the dimensions of the dispersed platelets and mainly from the type of nanocomposites formed upon mixing the clay particles with the polymer matrix. Compared to pure Nafion, the water uptake and the water diffusion of the hybrid membranes are increased, with the exception of the Kunipia-Nafion composite. A remarkable behaviour at high temperature is observed, where composite membranes maintain stable and unwavering diffusion for many hours and in conditions of not humidification, proving the exceptional water retention property of these materials. Finally the hybrid membranes are much stiffer and can withstand higher temperatures compared to pure Nafion, hence both these characteristics are highly desirable for use in fuel cell applications.
    Fuel and Energy Abstracts 04/2012; 37(7). DOI:10.1016/j.ijhydene.2011.06.041
  • [Show abstract] [Hide abstract]
    ABSTRACT: Polymer composite membranes based on sulfonated poly(phthalazinone ether sulfone) (SPPES) and zirconium sulfophenyl phosphate (ZrSPP) were prepared. Three ZrSPP concentrations were used: 10, 20, and 30 wt%. The membranes were characterized by infrared spectroscopy (IR), X-ray diffraction spectroscopy, thermal gravimetric analysis, and scanning electron microscopy (SEM). The IR results indicated the formation of intense hydrogen bonds between ZrSPP and SPPES molecules. The SEM micrographs showed that ZrSPP well dispersed with SPPES and form a lattice structure. The proton conductivity of the SPPES (degree of sulfonation (DS) 64 %)/ZrSPP (10 wt%) composite membrane reached 0.39 S/cm at 120 °C 100 % relative humidity and that of the 30 wt% of SPPES (DS 16.1 %)/ZrSPP composite membrane reached 0.18 S/cm at 150 °C. The methanol permeabilities of the SPPES/ZrSPP composite membranes were in the range of 2.1 × 10−8 to 0.13 × 10−8 cm2/s, much lower than that of Nafion®117 (10−6 cm2/s). The composite membranes exhibited good thermal stabilities, proton conductivities, and good methanol resistance properties.
    Ionics 07/2012; 19(7). DOI:10.1007/s11581-012-0818-5 · 1.75 Impact Factor
Show more