Drastic Enhancement of Activity and Durability for Oxygen Reduction Reaction by Melamine Modification for Platinum Nanocluster‐Loaded Electrocatalysts

To facilitate the widespread adoption of environmentally friendly fuel cells, it is essential to enhance the mass activity (MA) and durability of platinum (Pt) catalysts used in the oxygen reduction reaction (ORR). In this study, approximately 1 nm Pt nanocluster (NC)‐loaded carbon black (CB) (Pt NC/CB) catalysts were successfully prepared. The obtained Pt NC/CB catalysts exhibited up to 3.25 times higher ORR MA than commercial Pt nanoparticle (NP)/CB catalysts. Furthermore, the melamine‐modified Pt NC/CB catalysts achieved up to 6.37 times higher MA and 2.5 times higher durability than commercial Pt NP/CB catalysts. Notably, after durability testing, the melamine‐modified Pt NC/CB catalysts achieved 11.0 times higher ORR MA than that of the commercial Pt NP/CB. Although small Pt NCs were considered to be less durable than Pt NPs owing to their high surface energy, the strong interaction between the Pt NCs and melamine significantly enhances their activity and durability. These findings offer a pathway to significantly reduce Pt loading in polymer electrolyte fuel cells, contributing to their practical and widespread application.