Fabrication of La2O3/g-C3N4 Heterojunction with Enhanced Photocatalytic Performance of Tetracycline Hydrochloride

Synergistic Effects of Magnetic Z-Scheme g-C3N4/CoFe2O4 Nanofibres with Controllable Morphology on Photocatalytic Activity

The rational design of interfacial contacts plays a decisive role in improving interfacial carrier transfer and separation in heterojunction photocatalysts. In Z-scheme photocatalysts, the recombination of photogenerated electron-hole pairs is prevented so that the redox capacity is maintained. Here, one-dimensional graphitic carbon nitride (g-C₃N₄)/CoFe₂O₄ fibres were synthesised as a new type of magnetic Z-scheme visible-light photocatalyst. Compared with pure g-C₃N₄ and CoFe₂O₄, the prepared composite photocatalysts showed considerably improved performance for the photooxidative degradation of tetracycline and methylene blue. In particular, the photodegradation efficiency of the g-C₃N₄/CoFe₂O₄ fibres for methylene blue was approximately two and seven times those of g-C₃N₄ and CoFe₂O₄, respectively. The formation mechanism of the Z-scheme heterojunctions in the g-C₃N₄/CoFe₂O₄ fibres was investigated using photocurrent spectroscopy and electrochemical impedance spectroscopy. We proposed that one of the reasons for the improved photodegradation performance is that the charge transport path in one-dimensional materials enables efficient photoelectron and hole transfer. Furthermore, the internal electric field of the prepared Z-scheme photocatalyst enhanced visible-light absorption, which provided a barrier for photoelectron-hole pair recombination.

Facile Construction of Bi2Sn2O7/g-C3N4 Heterojunction with Enhanced Photocatalytic Degradation of Norfloxacin

To mitigate antibiotic residues in the water environment, Bi2Sn2O7/g-C3N4 (BSCN) heterojunction was fabricated by a facile ultrasound-assisted hydrothermal method. The microstructure, morphology, and optical properties of Bi2Sn2O7/g-C3N4 heterojunction was studied by XRD, FTIR, XPS, SEM, TEM, UV–Vis DRS, and PL. The degradation rate of 20 mg/L norfloxacin (NOR) under visible light for 3 h was adopted as one of the indexes to evaluate the photocatalytic performance of Bi2Sn2O7/g-C3N4 heterojunction. Embellished with 20% Bi2Sn2O7 (BSO), the Bi2Sn2O7/g-C3N4 heterojunction decomposed 94% NOR in the experimental solution, which was 2.35 and 3.03 times as much as pristine g-C3N4 and bare Bi2Sn2O7, respectively. In addition, the Bi2Sn2O7/g-C3N4 heterojunction still eliminated 89% of NOR after five cycles, portending outstanding stability and cyclability of photocatalytic activity. A possible photocatalytic mechanism of Bi2Sn2O7/g-C3N4 heterojunction for NOR degradation is proposed.

Ultrasound-Assisted Hydrothermal Synthesis of SrSnO3/g-C3N4 Heterojunction with Enhanced Photocatalytic Performance for Ciprofloxacin under Visible Light

In this work, an SrSnO3/g-C3N4 heterojunction with different dosage of SrSnO3 was fabricated by an ultrasound-assisted hydrothermal approach and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectra (UV-Vis DRS), and photoluminescence spectroscopy (PL). Ciprofloxacin was adopted to assess the degradation performance, and the sample combined with 40% SrSnO3 eliminated 93% of ciprofloxacin (20 mg/L) within 3 h under visible light, which is 6.6 and 1.7 times greater than for SrSnO3 and g-C3N4, respectively. Furthermore, 85% CIP was extinguished after five cycles of a photocatalytic process. Ultimately, a possible photocatalytic mechanism was dissected.