Durable N-doped carbon electrocatalysts derived from NH₃-activated coffee waste for the oxygen reduction reaction

Polymer electrolyte membrane fuel cells typically use expensive electrocatalysts comprising Pt-group metals (PGMs), particularly for the oxygen reduction reaction (ORR). However, PGMs can undergo surface poisoning resulting in severe performance deactivation. Therefore, metal-free electrocatalysts have been investigated as alternatives. In this study, N-doped carbon electrocatalysts for the ORR were derived from coffee waste (CW), which originates from carbonaceous natural resources. The electrocatalysts by CW recycling and simple thermal activation under NH₃ improve the electrocatalytic activity toward ORR and exhibit excellent durability in 40,000 cycles of accelerated stability tests. Although further investigation is required to optimize the electrochemical performance and gain deeper insights into the mechanistic roles of active sites, this simple strategy can promote cost-effective waste recycling and valorization for carbon neutrality.