Synthesis of a 3D Flower-Like BiOCl/Bi-MOF Heterostructure for High-Performance Removal of Rhodamine B and Tetracycline Hydrochloride.

Semiconductor materials based on bismuth metal have been extensively explored for their potential in photocatalytic applications owing to their distinctive crystal structure. Herein, we present the development of a hybrid photocatalyst, CAU-17/BiOCl, featuring a flower-like nanosheet morphology tailored for the photocatalytic degradation of organic contaminants such as rhodamine B (RhB) and tetracycline hydrochloride (TCH). The composite material is obtained by growing thin CAU-17 layers directly onto the host flower-like BiOCl nanosheets under solvothermal conditions. The optimized CAU-17/BiOCl composite possesses excellent photocatalytic performance, achieving a notable 96.0% removal rate for RhB and 78.4% for TCH after 60 and 90 min of LED light irradiation, respectively. This boosted activity is attributed to the heightened absorption of visible light caused by BiOCl and the provision of additional reaction sites due to the thin CAU-17 layers. Furthermore, the establishment of an S-scheme heterojunction mechanism enables efficient charge separation between CAU-17 and BiOCl, facilitating the separation of photoinduced electrons (e-) and holes (h+). Analysis of the degradation mechanism of RhB and TCH reveals the predominant role of superoxide radicals (•O2-), e-, and h+ in the photocatalytic degradation process. Moreover, the removal efficiency of TCH can reach approximately 64.5% after four cycles of recycling of CAU-17/BiOCl. Our work provides a facile, effective solution and a theoretically explained approach for the effective degradation of pollutants using heterojunction photocatalysts.

Construction of BiOCl/bismuth-based halide perovskite heterojunctions derived from the metal-organic framework CAU-17 for effective photocatalytic degradation.

The designed synthesis of an S-scheme heterojunction has possessed a great potential for improving photocatalytic wastewater treatment by demonstrating increased the photoredox capacity and improved the charge separation efficiency. Here, we introduce the fabrication of a heterojunction-based photocatalyst comprising bismuth oxychloride (BiOCl) and bismuth-based halide perovskite (BHP) nanosheets, derived from metal-organic frameworks (MOFs). Our composite photocatalyst is synthesized through a one-pot solvothermal strategy, where a halogenation process is applied to a bismuth-based metal-organic framework (CAU-17) as the precursor for bismuth sourcing. As a result, the rod-like structure of CAU-17 transforms into well-defined plate and nanosheet architectures after 4 and 8 h of solvothermal treatment, respectively. The modulation of the solvothermal reaction time facilitates the establishment of an S-scheme heterojunction, resulting in an increase in the photocatalytic degradation efficiency of rhodamine B (RhB) and sulfamethoxazole (SMX). The optimized BiOCl/BHP composite exhibits superior RhB and SMX degradation rates, achieving 99.8% degradation of RhB in 60 min and 75.1% degradation of SMX in 300 min. Also, the optimized BiOCl/BHP composite (CAU-17-st-8h sample) exhibited the highest rate constant (k = 3.48 × 10-3 min-1), nearly 6 times higher than that of the bare BHP in the photocatalytic degradation process of SMX. The enhanced photocatalytic efficiency can be endorsed to various factors: (i) the in-situ formation of two-components BiOCl/BHP photocatalyst, derived from CAU-17, effectively suppresses the aggregation of pristine BHP and BiOCl particles; (ii) the S-scheme heterostructure establishes a closely-knit interfacial connection, thereby facilitating efficient pathways for charge separation/transfer; and (iii) the BiOCl/BHP heterostructure enhances its capacity to absorb visible light. Our investigation establishes an effective strategy for constructing heterostructured photocatalysts, offering significant potential for application in photocatalytic wastewater treatment.

Cu2O/Fe3O4/MIL-101(Fe) nanocomposite as a highly efficient and recyclable visible-light-driven catalyst for degradation of ciprofloxacin.

Nowadays, the widespread production and use of antibiotics have increased their presence in wastewater systems, posing a potential threat to the environment and human health. The development of advanced materials for treating antibiotics in wastewater has always received special attention. This study aimed to synthesize a novel Cu2O/Fe3O4/MIL-101(Fe) nanocomposite and use it to degrade ciprofloxacin (CIP) antibiotics in an aqueous solution under visible light irradiation. The optical, structural, and morphological attributes of the developed nanocomposite were analyzed by XRD, FTIR, FE-SEM, TGA, DRS, BET, VSM, and UV-Vis techniques. Optimum circumstances for CIP photocatalytic degradation were acquired in 0.5 g L-1 of catalyst dosage, pH of 7, and CIP concentration of 20 mg L-1. The degradation efficiency was achieved 99.2% after 105 min of irradiation in optimum circumstances. The chemical trapping experiments confirmed that hydroxyl and superoxide radicals significantly contributed to the CIP degradation process. The results of this study indicated that Cu2O/Fe3O4/MIL-101(Fe) nanocomposite was a highly stable photocatalyst that could effectively remove antibiotics from aqueous solutions. The CIP degradation efficiency only decreased by 6% after five cycles, indicating the excellent recyclability of Cu2O/Fe3O4/MIL-101(Fe) nanocomposites.