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The construction of a Z-scheme heterojunction favors the improvement of the photocatalytic activity of photocatalysts. Herein, the LaVO 4 /Bi 3 O 4 Cl Z-scheme heterojunction was designed reasonably by the method of in situ growth. The obtained heterojunction was further used as a photocatalyst for the degradation of ofloxacin (OFX), an antibiotic, in wastewater. The degradation efficiency of OFX by the optimal sample (LBC-2) was 94.3 % and the values of k were about 114.7 and 2.4 times those of LaVO 4 and Bi 3 O 4 Cl, respectively. In addition, LBC-2 maintained high activity after 4 cycles. The significantly reduced recombination rate of carriers in LBC-2 was reflected by the results of the photoluminescence (PL), photocurrent (PC), and electrochemical impedance spectroscopy (EIS) studies. The degradation pathways of OFX were proposed accounting to the intermediates detected by liquid chromatography-mass spectroscopy (LC-MS). Toxicity estimations showed that the toxicity of some intermediates decreased. This work provides new insight into the development of Z-scheme photocatalysts for the removal of antibiotics as pollutants. • Novel Z-scheme LaVO 4 /Bi 3 O 4 Cl composite photocatalysts were synthesized. • LaVO 4 /Bi 3 O 4 Cl composites exhibited excellent activity for ofloxacin degradation. • The apparent rate constant for ofloxacin degradation was about 114.7 and 2.4 times as that of LaVO 4 and Bi 3 O 4 Cl. • Z-scheme heterojunction boosted the fast transfer of charge carriers. • The degradation pathway of ofloxacin was deduced. [ABSTRACT FROM AUTHOR]

LaFeO 3 /Bi 3 NbO 7 p-n heterojunction photocatalysts were prepared successfully through an in-situ growth method. The phase structure, optical property, morphology and microstructures of the obtained samples were studied by X-Ray diffractometer (XRD), Ultraviolet–visible absorption spectrum (UV–vis DRS), photoluminescence (PL) spectroscopy, transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM). The visible light responsive photocatalytic activity of as-obtained samples were investigated by the photo-reduction of Cr (Ⅵ). The effects of preparation conditions (proportion of BNO/LFO and temperature) on the activity were studied. Results showed that the as-obtained BNO-LFO-200-5 composite behaved the best photocatalytic activity (with rate constant of 0.0212 min−1) among all the obtained samples. The rate constant was about 42.4-times and 17.7-times as that of pristine BNO (0.0005 min−1) and LFO (0.0012 min−1), respectively. The enhanced photocatalytic property of the as-prepare LaFeO 3 /Bi 3 NbO 7 composites can be ascribed to the formation of p-n junction between BNO and LFO, which significantly increased the separation efficiency of photo-excited electron-holes. • A novel LaFeO 3 –Bi 3 NbO 7 p-n heterojunction photocatalyst was prepared for the first time. • The composites exhibited significantly enhanced activity for Cr (Ⅵ) photocatalytic reduction. • The heterojunctions promote the photo-generated carriers transmission and separation. [ABSTRACT FROM AUTHOR]

One of the current key issues in the photocatalysis is to obtain the band alignment of coupled semiconductor experimentally, which is the most significant aspect for understanding the efficient photocatalytic activity precisely. In this article, a BiVO 4 /BiOI{001} heterojunction was detected by the transmission electron microscopy (TEM). The results of electrochemical impedance spectroscopy (EIS) reveal that a higher efficiency of charge immigration across the electrode/electrolyte interface for the BiVO 4 /BiOI{001}. In addition, the electron lifetime was investigated by the Bode phase plots, which are responsible for the observed photocatalytic behaviors. As a result, the photocatalytic activities for rhodamine B (RhB) degradation and iodine ion oxidation are remarkably increased compared to the individual BiVO 4 and BiOI{001}. In fact, a direct band alignment in the BiVO 4 /BiOI{001} does not give well a logical interpreting on its photocatalytic behavior. However, through the valence-band offset formula, we demonstrated the exact band alignment of corresponding components in the BiVO 4 /BiOI{001}. This band alignment was further confirmed by the PL spectra, which CM2 with photo-oxidation (Mn 2+ ) is red shift and CM2 with photo-reduction (Ag + ) is blue shift compared with CM2. [ABSTRACT FROM AUTHOR]

A p-n-type Bi 5 O 7 I-modified porous g-C 3 N 4 nano-heterojunction is synthesized via a simple preparation technique using the template method and annealing-hydrothermal co-deposition method. The results of SEM, EDS, elemental mapping, XRD, TEM, XPS and FT-IR imply that the Bi 5 O 7 I nanoparticles were successfully deposited on the surface of the g-C 3 N 4 nanosheets. The photocatalytic activity of the as-prepared p-n-type nano-heterojunction remarkably exhibits an enhancement of 30 times that of the unmodified samples. Furthermore, the photocatalytic degradation enhancement mechanism has been studied, which could be ascribed to the p-n-type nano-heterojunction and lamellar-porous structure of the g-C 3 N 4 . [ABSTRACT FROM AUTHOR]

In the present work, a series of layered BiOBr/g-C 3 N 4 heterojunction photocatalysts were prepared via a simple reflux process, and their photocatalytic performance was investigated by the degradation of rhodamine B (RhB) and bisphenol A (BPA) under visible light irradiation. It was found that BiOBr nanoplates were deposited on the external surface of g-C 3 N 4 nanosheets (CNNS) and the tightly contacted interface was formed between two components, giving rise to a 2D porous layered heterojunction structure with a high specific area. It was found that BiOBr nanoplates coupled with the proper amount of CNNS exhibited an excellent photocatalytic performance due to the combined effects of layered heterojunction, high specific surface area and porous structure, which lead to the high efficiency of light harvesting and charge separation. The active species of OH is the most crucial one while h + and O 2 − contributed to a lesser extent in RhB and BPA photocatalytic degradation. Based on the direct evidence of the formed OH, O 2 − and h + active species detected by active species capture experiment and ESR spectra, a Z-scheme photocatalytic mechanism was proposed for the charge separation. The present work may provide an insight for designing novel layered Z-scheme heterojunction photocatalysts with a high performance. [ABSTRACT FROM AUTHOR]