Double-Solvent-Induced Derivatization of Bi-MOF to Vacancy-Rich Bi₄O₅Br₂: Toward Efficient Photocatalytic Degradation of Ciprofloxacin in Water and HCHO Gas

Abstract

MOF-derived photocatalytic materials have potential in degrading ciprofloxacin (CIP) in water and HCHO gas pollutants. Novel derivatization means and defect regulation are effective techniques for improving the performance of MOFderived photocatalysis. Vacancy-rich Bi 4 O 5 Br 2 (MBO-x) were derived in one step from Bi-MOF (CAU-17) by a modified double-solvent method. MBO-50 produced more oxygen vacancies due to the combined effect of the CAU-17 precursor and double solvents. The photocatalytic performance of MBO was evaluated by degrading CIP and HCHO. Thanks to the favorable morphology and vacancy structure, MBO-50 demonstrated the best photocatalytic efficiency, with 97.0% removal of CIP (20 mg L −1 ) and 90.1% removal of HCHO (6.5 ppm) at 60 min of light irradiation. The EIS Nyquist measurement, transient photocurrent response, photoluminescence spectra, and the calculation of energy band information indicated that the vacancy sites can effectively capture photoexcited electrons during the charge transfer process, thus limiting the recombination of electrons and holes, improving the energy band structure, and making it easier to produce superoxide anion radical (•O 2 − ) and to degrade CIP and HCHO. The improvement of photocatalytic performance of MBO-50 in HCHO degradation due to the bromine vacancy generation and filling mechanism was discussed in detail. This work provides a promising new idea for the modulation of MOF-derived photocatalytic materials.

Sepiolite-Supported Manganese Oxide as an Efficient Catalyst for Formaldehyde Oxidation: Performance and Mechanism

“…Other techniques include supported-manganese-based catalysts, in which manganese oxides are typically placed on high-specific-surface-area carrier materials, like zeolite [ 28 , 29 , 30 ], activated carbon (AC) [ 31 , 32 ], and MOF [ 33 ]. These carrier materials are primarily used to increase the dispersion degree of the active components and the super capture ability of HCHO and serve as a platform for designing and synthesizing manganese oxides with richer oxygen vacancies or metal defects that can activate surface oxygen species and H 2 O to degrade the captured HCHO into harmless CO 2 and H 2 O.…”