PtPd Hybrid Composite Catalysts as Cathodes for Proton Exchange Membrane Fuel Cells

Abstract

In this work, PtPd hybrid cathodic catalysts were prepared for a proton exchange membrane fuel cell (PEMFC) application by two different strategies. The first strategy was the physical mixing of bimetallic PtPd onto partially reduced graphene oxide (PtPd/rGO) and PtPd onto multi-walled carbon nanotubes (PtPd/MWCNT); (PtPd/rGO) + (PtPd/MWCNT). The second strategy was physical mixing of both carbonaceous supports before the PtPd deposition to form PtPd/(rGO:MWCNT). Our experimental results revealed that the PtPd nanomaterial prepared over a mixture of both carbonaceous supports had better oxygen reduction reaction (ORR) and PEMFC performances than the individually prepared catalysts. The insertion of MWCNT between rGO sheets prevented their stacking. This promoted the diffusion of oxygen molecules through the interlayer spacing, enhancing the ORR’s electrocatalytic activity. The durability test demonstrated that the hybrid supporting material dramatically improved the catalyst’s stability even after 3000 reaction cycles. This highlighted an increase greater than 100% for hybrid nanocomposites in their electrocatalytic activity as compared with the PtPd/rGO nanocomposite.

Iron Phthalocyanine/Graphene Composites as Promising Electrocatalysts for the Oxygen Reduction Reaction

“…One of the major obstacles in DMFC technology is the sluggish kinetics of the oxygen reduction reaction (ORR), which occurs at the cathode. This not only decreases the overall performance of DMFCs, but also requires a high loading of noble platinum (Pt) catalysts [3,4]. The mechanism of ORR usually follows either a two-step two-electron pathway or a one-step four-electron pathway.…”