Novel nanocomposite membranes based on cross-linked eco-friendly polymers doped with sulfated titania nanotubes for direct methanol fuel cell application

Abstract

Developing low cost and highly active fuel cell is one of the high-priority research directions for fuel cell commercialization, whereas durable electrodes and electrolyte membranes are keys for its optimization. Herein, a novel nanocomposite electrolyte membranes for direct methanol fuel cell were prepared from eco-friendly polymer blend composed of poly(vinyl alcohol) (PVA) and iota carrageenan (IC). Sulfated titania (SO4TiO2) nanotubes are synthesized by impregnation–calcination method and incorporated as doping agents into the polymer matrix with different percentage ranged between 1 wt% and .5 wt%. The PVA/IC/SO4TiO2 nanocomposite membranes exhibited reduction in water and methanol uptake compared to that of undoped membrane, while the thermal properties and oxidative stability increased as the doping agent content increased. Methanol permeability of PVA/IC/[Formula: see text]-TiO2-7.5 membrane was 0.62 × 10−7 cm2 s−1, which is 43 times lower than Nafion 117 (26.9 × 10−7 cm2 s−1). Furthermore, it was noticed that the ion exchange capacity and mechanical properties of the nanocomposite membranes are higher than that of Nafion 117.

Novel Crosslinked Sulfonated PVA/PEO Doped with Phosphated Titanium Oxide Nanotubes as Effective Green Cation Exchange Membrane for Direct Borohydride Fuel Cells

“…This behavior clarifies that PO 4 TiO 2 incorporation enhances the thermal stability of composite membranes by increasing the hydrogen bonding in the composite. For the DSC curves, as shown in Figure 5 b, the existence of only one endothermic peak provides a proof of complete miscibility in the membrane structure, and the disappearance of this peak at PO 4 TiO 2 (3 wt%) may be attributed to the formation of many hydrogen bonds between the doping agent and polymer structure [ 29 ]. The melting temperature of the membranes decreased with increasing doping agent concentration.…”

“…The melting temperature of the membranes decreased with increasing doping agent concentration. This behavior could be explained by the hydrogen bond interactions which partially destroy the membrane crystallinity, that in turn reduces the melting point and enhances the ionic conductivity [ 29 ].…”

“…To enhance the membrane properties many researchers have followed a common strategy of inserting doping agents into polymer structures to produce nanocomposite membranes [ 10 , 13 , 29 , 30 , 31 ]. phosphated titania (PO 4 TiO 2 ) incorporation into polymer matrices is attractive in fuel cell applications as a result of its large surface area, mechanical strength, chemical stability, fuel crossover barrier, low cost, and low toxicity [ 23 , 24 ].…”

Organic-Inorganic Novel Green Cation Exchange Membranes for Direct Methanol Fuel Cells

“…Gouda et al combined poly(vinyl alcohol) with IC through hydrogen bond interactions between the hydroxyl groups of the polymers for DMFCs. The results were an improvement in all the physicochemical properties [18,19].…”

“…Zirconium phosphate has hydrophilic phosphate groups which enhance water adsorption and increase proton conduction channels [27]. Upon merging of zirconium phosphate into polymers, hydrogen bonds will fabricate between polymer chains and zirconium phosphate, and these bonds will reinforce the membrane and compact it, as well as reducing the swelling and water uptake degree [18,28,29]. Further improvements in ionic conductivity of the membranes containing a high concentration of ZrPO 4 are possible due to the fact that it holds more acidic (phosphate) groups in its structure, which consequently increase the proton conduction channels [27].…”