Facilely synthesized porous 3D coral-like Fe-based N-doped carbon composite as effective Fenton catalyst in methylene blue degradation

Abstract In this study, a 3D Fe-based and N-doped coral-like carbon composite (Fe-NGLC) was successfully prepared via the simple impregnation of a self-made 3D nitrogen-enriched and porous layered graphene-like support with Fe2(SO4)3 as the precursor. It was characterized through X-ray diffractometry, scanning electron microscopy, X-ray photoelectron spectroscopy, etc.; Fe-NGLC exhibited regular three-dimensional coral-like structures with dense porosity and high of Fe–N species content. As a heterogeneous Fenton catalyst of the methylene blue (MB) degradation, the prepared composite showed impressive activity over a wide pH range (4–10). Almost 100% of the MB could be degraded in 60 min, and the results agreed well with the pseudo-first-order kinetic model. To identify the crucial active sites of MB degradation, the correlation between the rate constant derived from the pseudo-first-order kinetic model and the different Fe species in the catalyst prepared under various conditions was investigated. This revealed the key role of the Fe–N complexes for the heterogeneous Fenton reaction. Moreover, Fe-NGLC exhibited recyclability and only a slight decrease in removal efficiency after five cycles. The excellent performance of Fe-NGLC demonstrates its great potential as a Fenton catalyst for wastewater treatment.