Hydrophilicity is critical in Nafion membranes during fuel cell operation as insufficient membrane hydration leads to brittle behavior and a drop in proton conductivity.The incorporation of APTS(3-(aminopro pyl)trieth...Hydrophilicity is critical in Nafion membranes during fuel cell operation as insufficient membrane hydration leads to brittle behavior and a drop in proton conductivity.The incorporation of APTS(3-(aminopro pyl)triethoxysilane)into exfoliated graphene oxide(EGO)by covalent functionalization to be used as filler into Nafion membranes allows higher hydrophilicity for these membranes.This is associated with promoting hydroxyl,carbonyl,siloxane,silane,and amine groups within the EGO-APTS matrix.The incorporation of these materials as Fuel Cell MEAs leads to a significant reduction of the ohmic resistance measured at high frequency resistance(HFR)in electrochemical impedance spectroscopy(EIS)experiments and achieves maximum power densities of 1.33 W cm^(-2)at 60℃ at 100%RH(APTS-EGO,0.2 wt%)and1.33 W cm^(-2)at 60℃ at 70%RH(APTS-EGO,0.3 wt%),which represents an improvement of 190%compared to the commercial Nafion 212 when utilizing low humidification conditions(70%).Moreover,the as-synthesized membrane utilizes lower Nafion ionomer mass,which,in conjunction with the excellent cell performance,has the potential to decrease the cost of the membrane from 87 to 80￡/W as well as a reduction of fluorinated compounds within the membrane.展开更多
A homogeneous dispersion of multiwall carbon nanotubes(MWNT) was achieved by dispersing MWNT into 0.1% Nafion ethanol solution, and a uniform cast film at a glassy carbon electrode(GCE) was obtained via solvent evapor...A homogeneous dispersion of multiwall carbon nanotubes(MWNT) was achieved by dispersing MWNT into 0.1% Nafion ethanol solution, and a uniform cast film at a glassy carbon electrode(GCE) was obtained via solvent evaporation of the MWNT dispersion. A reversible two-electron redox reaction of dopamine was observed at the MWNT-Nafion modified GCE. In comparison with a bare GCE and a Nafion-modified GCE, MWNT-Nafion modified GCE has a higher sensitivity for dopamine. This modified GCE has an excellent selectivity towards dopamine even in the presence of high concentration ascorbic acid(AA) and uric acid(UA) since AA and UA have no observable electrochemical responses at the modified GCE. The electrochemical behavior of dopamine was closely related to the pH of the buffer solution. The oxidation peak current was proportional to the concentration of dopamine over the range from 5×10 -8 to \{1×\}10 -6 mol/L, and a detection limit of 2.5×10 -9 mol/L was obtained after 3 min open-circuit accumulation. The dispersion and morphology of MWNT-Nafion film were investigated by transmission electron microscopy(TEM).展开更多
基金financially supported by the UK Research Council EPRSC EP/W03395X/1the Program grant SynHiSel EP/V047078/1the Hydrogen and Fuel Cells Hub(H_(2)FC SUPERGEN)EP/P024807/1。
文摘Hydrophilicity is critical in Nafion membranes during fuel cell operation as insufficient membrane hydration leads to brittle behavior and a drop in proton conductivity.The incorporation of APTS(3-(aminopro pyl)triethoxysilane)into exfoliated graphene oxide(EGO)by covalent functionalization to be used as filler into Nafion membranes allows higher hydrophilicity for these membranes.This is associated with promoting hydroxyl,carbonyl,siloxane,silane,and amine groups within the EGO-APTS matrix.The incorporation of these materials as Fuel Cell MEAs leads to a significant reduction of the ohmic resistance measured at high frequency resistance(HFR)in electrochemical impedance spectroscopy(EIS)experiments and achieves maximum power densities of 1.33 W cm^(-2)at 60℃ at 100%RH(APTS-EGO,0.2 wt%)and1.33 W cm^(-2)at 60℃ at 70%RH(APTS-EGO,0.3 wt%),which represents an improvement of 190%compared to the commercial Nafion 212 when utilizing low humidification conditions(70%).Moreover,the as-synthesized membrane utilizes lower Nafion ionomer mass,which,in conjunction with the excellent cell performance,has the potential to decrease the cost of the membrane from 87 to 80￡/W as well as a reduction of fluorinated compounds within the membrane.
文摘A homogeneous dispersion of multiwall carbon nanotubes(MWNT) was achieved by dispersing MWNT into 0.1% Nafion ethanol solution, and a uniform cast film at a glassy carbon electrode(GCE) was obtained via solvent evaporation of the MWNT dispersion. A reversible two-electron redox reaction of dopamine was observed at the MWNT-Nafion modified GCE. In comparison with a bare GCE and a Nafion-modified GCE, MWNT-Nafion modified GCE has a higher sensitivity for dopamine. This modified GCE has an excellent selectivity towards dopamine even in the presence of high concentration ascorbic acid(AA) and uric acid(UA) since AA and UA have no observable electrochemical responses at the modified GCE. The electrochemical behavior of dopamine was closely related to the pH of the buffer solution. The oxidation peak current was proportional to the concentration of dopamine over the range from 5×10 -8 to \{1×\}10 -6 mol/L, and a detection limit of 2.5×10 -9 mol/L was obtained after 3 min open-circuit accumulation. The dispersion and morphology of MWNT-Nafion film were investigated by transmission electron microscopy(TEM).
