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.