In Situ Electrochemical Deposition of Pt Metal Particles Using Nafion® Membrans as the Template

Nafion ® membrane is one of the most commonly used electrolytes in methanol and hydrogen fuel cells. Under operating conditions this membrane absorbs water and phase separates into hydrophobic and hydrophilic domains. To produce electrical energy in a fuel cell, the hydrophilic domains must provide a continuous pathway for protons produced at the anode to the cathode and also have a catalyst particle at both ends at the nafion ® electrode interphase. Recently it has been shown that the Pt catalyst can be deposited electrochemically through the hydrophilic channels of the Nafion ® membrane. This method places the catalyst only in the hydrophilic domains and avoids the waste resulting from Pt placed under the hydrophobic regions of the membrane. The progress of the Pt deposition was characterized using Cyclic Voltammetry (CV) of methanol oxidation and the available surface area of the catalyst was calculated from the under potential deposition of Cu using stripping voltammetry. Once the fuel cell is constructed using this technique, it will be tested using the fuel cell test station (850C-Scribner Associates), for hydrogen varying parameters such as the relative humidity, anode and cathode temperatures etc. Also the same techniques will be utilized to construct direct methanol fuel cells using co deposited Pt and Ru as the catalyst. This method can be utilized to deposit metal catalysts in fuel cell fabrication and has the potential to reduce the catalyst loading by 10 3 to 10 6 folds to get the similar or may be higher efficiency than conventional fuel cells.