Do Melamine and Melamine-Formaldehyde Surface Modifiers Improve Fuel Cell Activity and Durability?

Precious group metal-based catalysts based on Pt- and Pt-alloys are currently used as catalysts for the kinetically sluggish Oxygen Reduction Reaction (ORR) on the cathode of fuel cells. The activity of Pt or Pt-alloy catalysts towards ORR is severely compromised by the adsorption of spectator-species such as sulfonate anions from perfluorosulfonic acid (PFSA) ionomer or Pt-O(H)ad via water activation. Considering recent evidence pointing to the improvement in ORR activity via the use of melamine organic molecule or melamine-formaldehyde copolymeric additives as surface blocking agents for the prevention of sulfonate or Pt-OHad adsorption, we evaluated these additives in fuel cells. The catalysts were modified with either of these additives and characterized using ex situ and in situ methods to verify successful adsorption and eventual performance in fuel cells. These surface modifying agents were found to suppress Pt-OHad formation as well as suppress ORR activity. There was no evidence to point out that these additives improved ORR activity and H2/air polarization performance in a fuel cell MEA on supported, polycrystalline Pt catalyst.

Automated summary

Precious group metal-based catalysts, such as Pt and Pt-alloys, are commonly used in fuel cell cathodes for the Oxygen Reduction Reaction (ORR). However, their activity is hindered by the adsorption of spectator species, such as sulfonate anions, which compromises the ORR performance. Recent research has shown that the use of melamine organic molecules or melamine-formaldehyde copolymeric additives can improve the ORR activity. In this study, the effectiveness of these additives in fuel cells was evaluated, and it was found that they can suppress adsorption but do not enhance the ORR activity.