Researchers at Tohoku University have developed a catalyst that can partially renew itself during operation, offering a pathway toward longer lasting materials for energy and chemical applications. The catalyst is designed for the oxygen reduction reaction a key process in fuel cells and other clean energy technologies.

The material was created by coating carbon nanotubes with a thin layer of iron polyphthalocyanine (FePPc). This approach enabled a higher loading of iron compared with previous methods, while preserving the same type of active sites that drive the reaction. When tested in acidic conditions, the catalyst exhibited strong oxygen conversion performance, with clear signs of efficient electron transfer and favorable reaction pathways. The researchers attributed this activity to the intimate interaction between the FePPc shell and the nanotube surface.

Durability proved equally impressive. In long term tests, the catalyst maintained about 80% of its initial activity after 24 hours, whereas a similar material lacking the polymerized shell lost most of its activity within only a few hours.

Further investigation revealed that the catalyst evolves dynamically under operating conditions. Thin FePPc layers gradually detach, exposing fresh active sites, while some detached fragments temporarily redeposit onto the nanotubes and continue to assist the reaction. Over time, however, dissolved iron aggregates into stable clusters, which diminishes activity.

Our results show that the apparent stability of the catalyst depends on a balance between the renewal of active sites and the gradual processes that deactivate them, explained Hao Li, Distinguished Professor at Tohoku University’s Advanced Institute for Materials Research. By understanding this dynamic evolution, we can build a foundation for designing Fe–N–C catalysts that remain effective under demanding electrochemical conditions.

By revealing the self renewal mechanism, the study provides new insights for developing durable catalysts to power clean energy devices and enable the sustainable production of chemicals from renewable resources.

Sourcel :https://www.tohoku.ac.jp/en/press/dynamic_evolution_of_fenc_catalysts_for_oxygen_reduction_in_acid.html