Fabrication of CN75/NH2-MIL-53(Fe) p-n heterojunction with wide spectral response for efficiently photocatalytic Cr(VI) reduction

In this study, p-type carbon nitride (CN75) nanoparticles were introduced to precursors of NH2-MIL-53(Fe). A CN75 and NH2-MIL-53(Fe) p-n heterojunction was formed by solvothermal reaction. It showed that tiny loading of CN75 onto NH2-MIL-53(Fe) would boost the separation, migration and transfer of photo-induced carriers effectively. Meanwhile, its spectral response was broadened, which draw in efficient photocatalytic performance together. As for photocatalytic reduction of Cr(VI), the rate constant on CN75/NH2-MIL-53(Fe) was ca 1.8 and 25.3 times that by NH2-MIL-53(Fe) and CN75 under visible light (λ ≥ 420 nm), respectively. Reduction rate of CN75/NH2-MIL-53(Fe) (0.1 g/L) reached about 100% within 15 min at pH 2. Good activity could also be observed even under red light (λ: 650–660 nm). Besides, CN75/NH2-MIL-53(Fe) exhibited high stability after 5 cyclic runs, and the leaching of Fe3+ can be greatly suppressed after loading CN75. Structural analysis proved that the MOFs framework was well maintained. Thus, this research paper would provide useful information about the construction and synthesis of efficient and steady Fe-MOFs based photocatalyst for environmental remediation.