Visible Light-Driven BiOBr/Bi2S3@CeMOF Heterostructured Hybrid with Extremely Efficient Photocatalytic Reduction Performance of Nitrophenols: Modeling and Optimization

摘要

The one-pot facile solvothermal process was applied to designed BiOBr/Bi2S3 heterostructured microspheres. The hierarchical BiOBr/Bi2S3 photocatalyst is integrating by solid-state adding of cerium based metal-organic frameworks (CeMOF) using ball mill to fabricate a novel BiOBr/Bi2S3@CeMOF. The synthesized photocatalysts were examined by XRD (X-Ray diffraction), Raman, FTIR (Fourier transform infrared spectroscopy), XPS (X-Ray photoelectron spectroscopy), FESEM (field emission transmission electron microscopy), FETEM (field emission scanning electron microscopy), UV-Vis DRS (ultraviolet-visible diffuse reflectance), PL (Photoluminescence), and transient photocurrent analysis. The as-prepared BiOBr/Bi2S3@CeMOF photomaterial displays considerably enhanced photocatalytic activity for reduction of 4-nitrophenol (4NP) to 4-aminophenol (4AP) compared with the pristine BiOBr and BiOBr/Bi2S3 composite under the irradiation of visible light. The promising BiOBr/Bi2S3@CeMOF photocatalyst exhibit the highest photoreduction efficiency of 4NP along with the highest reaction rate (K) (R: 98 %; K: 3.91 min(-1) ) compared with the other as-prepared materials such as CeMOF (R:38 %; 0.23 min(-1)), BiOBr (R: 48 %; K: 0.65 min(-1)), Bi2S3 (R:68 %;0.92 min(-1)), and BiOBr/Bi2S3 (R: 75 %; K: 1.38 min(-1)) photocatalysts after 30 min of visible light irradiation. The boosted photocatalytic efficiency is attributed to creating the heterojunction at the interface of BiOBr/Bi2S3@CeMOF, which can powerfully facilitate the separation of the photogenerated carriers. After that, the Box-Behnken design was applied to indicate the optimum condition for the reduction of 4NP under the effect of different variables (e. g., the concentration of NP (A:), pH (B), and concentration of NaBH4 (C). At the optimum condition (A: 14.5 mu mol L-1, B: 5, and C: 0.88 mol L-1), the photoreduction efficiency (%) of the 4NP is 99.7 %. BiOBr/Bi2S3@CeMOF catalyst exhibits excellent photoreduction stability over five successive reaction runs.