A 2D/1D heterojunction nanocomposite built from polymeric carbon nitride and MIL-88A(Fe) derived α-Fe2O3 for enhanced photocatalytic degradation of rhodamine B

Fabricating heterojunction catalysts is a promising strategy for enhancing the performance of heterogeneous photocatalytic reactions. Based on the nontoxicity and low cost of photocatalyst, we synthesized two dimensional/one dimensional (2D/1D) heterojunction photocatalysts, namely alpha-Fe2O3/C3N4-x% (FC-x = 4, 8, and 12) containing alpha-Fe2O3 microrods and polymeric carbon nitride (C3N4) flakes through the calcination of Fe-based metal-organic framework (MIL-88A(Fe)) with C3N4 for boosting visible light photocatalytic degradation of rhodamine B (RhB). The synthesized composite materials are characterized by FTIR, PXRD, UVDRS, PL, FESEM, TEM, BET and TG/GC/MS analysis. Due to the 2D/ID heterojunction formation between C3N4 and alpha-Fe2O3, the band gap of alpha-Fe2O3/C3N4 composite (FC-8) is reduced to 2.05 eV compared to C3N4 and alpha-Fe2O3. The hybrid system alpha-Fe2O3/C3N4-8% (FC-8) showed excellent photocatalytic activity for the degradation of RhB under sunlight. The hybrid FC-8 shows 92% degradation of RhB in 60 min under sunlight. A possible Z-scheme mechanism for the enhanced photocatalytic activity of the FC-8 composite is also proposed. More importantly, the fabricated 2D/1D heterojunction between alpha-Fe2O3 and C3N4 efficiently speeds up the transfer and separation of photoinduced charge carriers, which is beneficial for photocatalytic activity. Trapping experiments revealed that superoxide radicals are the prime radicals responsible for the degradation of RhB. The hybrid system FC-8 showed high recyclability and chemical stability.

Automated summary

Fabricating 2D/1D heterojunction photocatalysts (alpha-Fe2O3/C3N4) can effectively enhance the performance of visible light photocatalytic reactions. The reduction of band gap due to the heterojunction formation between C3N4 and alpha-Fe2O3 leads to excellent photocatalytic activity. The proposed Z-scheme mechanism of FC-8 composite and its high recyclability and chemical stability demonstrate the importance of this research.