Au nanoparticles self-assembled onto Nafion membranes for use as methanol-blocking barriers

Charged Au nanoparticles were prepared by refluxing a solution of hydrogen tetrachloroaurate trihydrate and protective cationic agents, PDDA, in ethanol/water. The Au nanoparticle showed zeta potential of 32 mV and size of about 4 nm. The charged Au nanparticles were self-assembled onto the Nafion™ 212 membrane surface as methanol barriers and the methanol crossover decreases from 168 to 18 mA/cm2 at the condition of 2 mol/L methanol, 60 °C. All the self-assembled PEMs have higher OCV and performance than original Nafion 212 membrane. And the PEMs self-assembled for 24 h have the highest performance due to the decrease of the methanol permeation current density and acceptable membrane area resistance.