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BACKGROUND: Ferrocene (Fc) is a chemically stable, safe and non‐toxic substance with excellent redox performance and is often used to activate various oxidants. However, Fc is a nanoscale non‐magnetic material, which needs a suitable carrier such as chitosan (CS) to be fixed and being compounded with magnetic material for recycling. RESULTS: A new magnetic catalyst, Fc/CS@Fe3O4, was prepared for activating persulfate (PS) to degrade tetracycline (TC) in water. The catalyst prepared was characterized by X‐ray powder diffraction, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy and vibrating sample magnetometry, and the effects of the dosage of PS and catalyst, pH, temperature, coexisting anions and fulvic acid on TC degradation were investigated. The results showed that the removal of TC could be promoted by increasing the temperature, and acidic conditions are more beneficial to TC degradation than alkaline conditions. Cl−, CO32−, HCO3− and fulvic acid could all inhibit the degradation of TC. Light and catalyst had a synergistic activation effect on PS. Under conditions of PS and catalyst dosage all 400 mg L−1, temperature 25° C, TC concentration 30 mg L−1 and initial pH 5, TC could be completely degraded within 60 min. Both SO4−• and HO• contributed to TC degradation, and SO4−• was the main active species in the degradation system. CONCLUSION: The results indicate that Fc/CS@Fe3O4 has good catalytic activity and stability, and has potential application in the treatment of antibiotics in water. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

BACKGROUND: Bismuth tetraoxide (Bi2O4) has attracted increasing interest as a novel visible‐light‐driven photocatalyst. It suffers from some drawbacks, such as quick recombination of photogenerated electrons and holes, small specific surface area and few active sites due to submicron rod structure. RESULTS: A novel and efficient binary heterojunction photocatalyst, in which zero‐dimensional (0D) SnO2 nanoparticles was anchored on the surface of one‐dimensional (1D) Bi2O4 micrometer rods, was successfully synthesized. The as‐prepared samples were characterized by X‐ray diffraction (XRD), scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The photocatalytic activity of the synthesized photocatalysts was evaluated by photodegradation of tetracycline (TC) under visible‐light irradiation. The prepared 30‐SB composite (30 wt% SnO2/Bi2O4) exhibits the highest photocatalytic activity toward TC degradation. The removal efficiency of TC was up to 84.3% within 120 min. The rate constant k for the reaction of 30‐SB composite is 0.029017 min−1, which is 13.4 and 1.8 times as high as that of SnO2 and Bi2O4, respectively. CONCLUSION: The significantly boosted photocatalytic activity is attributed to the formation of Z‐scheme heterojunctions between SnO2 and Bi2O4. Z‐scheme charge transfer promoted the effective separation of photogenerated carriers and ensured that the holes with higher oxidative activity and electrons with stronger reducibility participate in the production of •OH and •O2− as well as direct degradation of TC. This work will provide a new modification strategy for the potentially excellent photocatalyst Bi2O4. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

A novel ternary heterojunction composite photocatalyst g-C3N4/TiO2/NiWO4 was fabricated using a simple hydrothermal method. The synthesized samples were characterized using X-ray diffraction (XRD), scanning electronic microscopy (SEM), energy-dispersive spectrum (EDS), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) absorption spectra, photoluminescence (PL) spectra, transient photocurrent responses, and electrochemical impedance spectroscopies (EIS). The results indicated that the composite of g-C3N4/TiO2/NiWO4 had been successfully synthesized. By constructing a ternary heterojunction, the electron migration rate and light absorption of the material are further improved; the photogenerated electron–hole recombination is inhibited. The ternary composite photocatalyst shows the highest photocatalytic activity for the degradation of rhodamine B (RhB) than that of g-C3N4, TiO2, NiWO4, and g-C3N4/TiO2 photocatalyst. The degradation efficiency of RhB using g-C3N4/TiO2/NiWO4 can reach 99% after visible-light irradiation for 40 min. Finally, the migration mechanism of charge carriers in the ternary system has been schematically illustrated by the active species capture experiment. Our research can pave the way for the fabrication of ternary heterojunction composite photocatalyst with high photocatalytic activity for the environmental contaminants treatment. [ABSTRACT FROM AUTHOR]

BACKGROUND: A Z‐scheme structured photocatalyst is a highly efficient photocatalyst for hydrogen evolution and degradation of pollutants. RESULTS: An indirect Z‐scheme heterojunction g‐C3N4/CQDs/InVO4 with carbon quantum dots (CQDs) as electron mediator was constructed and was successfully synthesized using a facile hydrothermal method. The photocatalytic activity of the as‐prepared composite was evaluated in terms of hydrogen generation and degradation of rhodamine B (RhB) dye. The as‐prepared sample CV20/CQDs2 (g‐C3N4/2 wt% CQDs/20 wt% InVO4) exhibits the best photocatalytic activity towards hydrogen production and RhB degradation. Within 90 min, 99.6% of RhB is removed, and the degradation rate constant of RhB over CV20/CQDs2 is 0.06491 min−1, which is 43.9, 6.64 and 3.3 times as high as that of InVO4, g‐C3N4 and binary composite g‐C3N4/InVO4. CV20/CQDs2 exhibits H2 evolution rate of 2.169 mmol g−1 h−1, which is 26.07, 2.65 and 1.6 times as high as that of InVO4, g‐C3N4 and g‐C3N4/InVO4. CONCLUSIONS: The enhanced photocatalytic activity is attributed to two aspects. First, CQDs, as electron mediator, promote the effective separation of photogenerated electrons and holes through Z‐scheme charge transfer pathway, preserving the high redox ability of electrons and holes. Second, g‐C3N4/CQDs/InVO4 shows strong optical absorption in the full visible‐light region. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Improving the photocatalytic performance of metal-organic frameworks (MOFs) is an important way to expand its potential applications. In this work, zero-dimensional (0D) Bi 2 O 3 nanoparticles were anchored to the surface of tridimensional (3D) MIL101(Fe) by a facile solvothermal method to obtain a novel 0D/3D heterojunction Bi 2 O 3 /MIL101(Fe) (BOM). The morphology and optical properties of the as-prepared Bi 2 O 3 /MIL101(Fe) composite were characterized. The photocatalytic activity of the synthesized samples was evaluated by degrading chlortetracycline (CTC) under visible-light irradiation. The obtained BOM-20 composite (20 wt % Bi 2 O 3 /MIL101(Fe)) exhibits the highest photocatalytic activity with CTC degradation efficiency of 88.2% within 120 min. The degradation rate constant of BOM-20 toward CTC is 0.01348 min -1 , which is 5.9 and 4.3 times higher than that of pristine Bi 2 O 3 and MIL101(Fe), respectively. The enhanced photocatalytic activity is attributed to the formation of a Z-scheme heterojunction between Bi 2 O 3 and MIL101(Fe), which is conducive to the rapid separation of photogenerated carriers and the enhancement of photogenerated electron and hole redox capacity. The intermediate products were analyzed by liquid chromatography-mass spectrometry (LC-MS), and a possible photocatalytic degradation path of CTC was proposed. This work provides a new perspective for the preparation of efficient MOF-based photocatalysts., (Copyright © 2022, Hao et al.)