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摘要
To elevate the operating temperature of proton exchange membranes (PEMs) to 200 degrees C under anhydrous conditions, in the current work, the protic ionic liquid, 1-methylimidazolium trifluoromethanesulfonate ([MIm][Tfo]), was used as an anhydrous proton conductor and integrated with a superabsorbent host polyacrylamide/polyethylene glycol interpenetrated polymer network (PAM/PEG IPN) by doping and adsorbing methods. The resultant membranes could be operated up to 200 degrees C under nonhumidified conditions, showing a proton conductivity of 17.02 and 10.37 mS cm(-1) at 150 degrees C for [MIm][Tfo] doped and adsorbed PAM/PEG IPN membranes, respectively. Because of the intrinsic nature of the PAM/PEG IPN superabsorbent, the loaded [MIm][Tfo] could not leak from the PEM systems even under high temperatures and pressures. A percolation phenomenon was observed because of the formation of proton-conducting channels for proton transfer. The new PEM presented a maximum tensile strength of 12.4 MPa and elongation of 1068% and 10.0 MPa and 1594% for the membranes by doping and adsorbing methods, respectively. To increase the electrocatalytic activity and decrease the cost of the catalyst, we also developed a well-aligned low-Pt anode catalyst using a fir template, exhibiting high activity for methanol oxidation reaction. When the methanol gas was bubbled into [MIm][Tfo] around the anode catalyst parallel to its channels, the oxidation current density at 200 degrees C was 8.7 times larger than that at 25 degrees C, whereas it was 5.4 times larger at 200 degrees C than that at 25 degrees C perpendicular to its channels. The membranes and efficient catalysts are possible candidates for direct methanol fuel cells that operate at high temperature and anhydrous conditions. The use of superabsorbents opens up a new route to high-temperature PEMs.
- 出版日期2011
- 单位华侨大学
