Fe-N-Graphene Wrapped Al₂O₃/Pentlandite from Microalgae: High Fenton Catalytic Efficiency from Enhanced Fe³⁺ Reduction

Efficient cycling of Fe³⁺/Fe²⁺ is a key step for the Fenton reaction. In this exploration, from microalgae, we have prepared a novel Fe-N-graphene wrapped Al₂O₃/pentlandite composite which showed high Fenton catalytic ability through accelerating of Fe³⁺ reduction. The catalyst exhibits high activity, good reusability along with stability, and wide adaptation for the organics degradation under neutral pH. High TON and H₂O₂ utilization efficiency have also reached by this catalyst. Characterization results disclose a unique structure that the layered Fe-N-graphene structure tightly covers on Al₂O₃/pentlandite particles. Mechanistic evidence suggests that the accelerated Fe³⁺/Fe²⁺ redox cycle originates from the enhanced electron transfer by the synergistic effect of Fe, Ni and Al in the catalyst, and it causes the low H₂O₂ consumption and high •OH generation rate. Moreover, organic radicals formed in the Fenton process also participate in the Fe³⁺ reduction, and this process may be accelerated by the N doped graphene through a quick electron transfer. These findings stimulate an approach with great potential to further extend the synthetic power and versatility of Fenton catalysis through N doped graphene in catalysts.