Optimizing Reduced Graphene Oxide with Metallic Nanoparticles for Increasing the Efficiency of Proton Exchange Membrane
- PDF / 27,541,180 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 47 Downloads / 246 Views
Optimizing Reduced Graphene Oxide with Metallic Nanoparticles for Increasing the Efficiency of Proton Exchange Membrane Fuel Cells Rebecca Isseroff1,2, Arthur Chen2, Lee Blackburn2, Justin Lish3, Long Tao Han1, Hongfei Li1, Miriam Rafailovich1 1
Dept. of Materials Science and Chemical Engineering, SUNY Stony Brook, Stony Brook, NY, United States. 2 Lawrence High School, Cedarhurst, NY, United States 3 Hebrew Academy of the Five Towns and Rockaways, Cedarhurst, NY, United States
ABSTRACT The oxidation of CO to CO2 is necessary in the operation of Proton Exchange Membrane Fuel Cells (PEMFCs) since even a small amount of CO that is formed when the PEMFC is operated under ambient conditions is sufficient to poison the Pt catalyst in the electrodes and degrade the performance. Operation using higher loads of Pt catalysts or increasing the purity of the H2 input gas significantly adds to the cost, adversely impacting the commercial development of PEMFCs. We combined graphene oxide (GO) with metallic salts and partially reduced the mixture with sodium borohydride, yielding a metallized form of partially reduced graphene oxide (prGO) platelets that remained in solution. When these platelets were coated on the Nafion membrane of a PEMFC, a 72% increase in the power output was observed, whereas a 62% increase was observed when the membrane was coated with partially reduced graphene oxide without the metallic salts. Results will be presented for AuGO/prGO, PtGO/prGO, and AuPtGO/prGO combinations. INTRODUCTION A major difficulty with Proton Exchange Membrane Fuel Cells (PEMFCs) is that the platinum catalysts are highly susceptible to carbon monoxide poisoning [1]. Carbon monoxide forms during the reverse water shift reaction, as seen in equation 1[2]: CO + H2O
CO2 + H2
(1)
Generally this issue is resolved by the use of pure hydrogen and increasing the amount of platinum catalysts. However, the production of pure hydrogen is exceedingly expensive because of the use of a pure platinum membrane during the purification process [3]. Also, due to its commercialized use, PEM fuel cells will often be exposed to CO2 in the air. The performance of PEM fuel cells are also limited by the polymer electrolyte membrane. For instance, Nafion, one of the oldest and most widely used polymer electrolyte membranes, limits the maximum operating temperature of fuel cells to 80°C due to the degradation of the membrane at higher temperatures [4]. This limitation of temperature requires the use of pure hydrogen gas, since CO doesn't oxidize to CO2 at temperatures below 100°C.
Gold nanoparticles have been shown to catalyze the oxidation of CO to CO2 [5]. However, aggregation, a common yet complex phenomenon for small particles, is problematic. Known to decrease the surface-area to volume ratio, it also attracts nanoparticles closer to each other, resulting in their interaction and possibly altering the distinctive characteristics that make nanoparticles unique [6]. Although researchers have attached ligands to stabilize nanoparticles from becomin
