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

Abstract

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 α-Fe₂O₃/C₃N₄-x% (FC-x = 4, 8, and 12) containing α-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 α-Fe₂O₃, the band gap of α-Fe₂O₃/C₃N₄ composite (FC-8) is reduced to 2.05 eV compared to C₃N₄ and α-Fe₂O₃. The hybrid system α-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 α-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.