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A novel Z-scheme ZnFe2O4/BiVO4 heterojunction photocatalyst was successfully synthesized using a convenient solvothermal method and applied in the visible light photocatalytic degradation of ciprofloxacin, which is a typical antibiotic contaminant in wastewater. The heterostructure of as-synthesized catalysts was confirmed using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy characterizations. Compared with the single-phase counterparts, ZnFe2O4/BiVO4 demonstrated considerably enhanced photogenerated charge separation efficiencies because of the Z-scheme transfer mechanism of electrons between the composite photocatalysts. Consequently, the 30% ZnFe2O4/BiVO4 catalyst afforded a degradation rate of up to 97% of 20 mg/L ciprofloxacin under 30 min of visible light irradiation with a total organic carbon removal rate of 50%, which is an excellent activity compared with ever reported BiVO4-based catalysts. In addition, the liquid chromatography-mass spectrometry and quantitative structure-activity relationships model analyses demonstrated that the toxicity of the intermediates was lower than that of the parent ciprofloxacin. Moreover, the as-synthesized ZnFe2O4/BiVO4 heterojunctions were quite stable and could be reused at least four times. This study thus provides a promising Z-scheme heterojunction photocatalyst for the efficient removal and detoxication of antibiotic pollutants from wastewater. [ABSTRACT FROM AUTHOR]

Utilization of spontaneous polarization electric field of ferroelectric materials to realize the spatial separation and fast transfer of photogenerated charges has been regarded as a promising strategy to fabricate highly efficient photocatalysts. Herein, a novel heterostructure is constructed by coupling potassium poly(heptazine imide) (K‐PHI) with ferroelectric BaxSr1‐xTiO3 (BxST) through a facile electrostatic self‐assembly strategy. The ionic species of K‐PHI can neutralize the polarized charges in BxST to form intimate interfacial contact, substantially boosting the internal electric field. Notably, K+ cations intercalated into K‐PHI act as charge‐transfer bridge to promote migration and separation of photogenerated charge carriers. As a result, a significantly improved H2‐evolution rate of 1087.4 µmol h−1 g−1 with an apparent quantum yield (AQY) of 8.05% at 420 nm is achieved over 5% K‐PHI/B0.8ST, standing among the best polymeric carbon nitride‐based photocatalysts reported up to date. Moreover, the extreme stability of the catalysts is evidenced by remaining outstanding catalytic performance even after storage for half a year. This strategy can be extended to other alkali metal (Na+ and Cs+) modified polymeric materials, highlighting the key role of the bridging ions in constructing polarized heterostructure, which sheds light on the design of ferroelectric‐assisted photocatalysts. [ABSTRACT FROM AUTHOR]

It is of broad interest to develop emerging photocatalysts with excellent light-harvesting capacity and high charge carrier separation efficiency for visible light photocatalytic hydrogen evolution reaction. However, achieving satisfying hydrogen evolution efficiency under noble metal-free conditions remains challenging. In this study, we demonstrate the fabrication of three-dimensionally ordered macroporous SrTiO3 decorated with ZnxCd1−xS nanoparticles for hydrogen production under visible light irradiation (λ > 420 nm). Synergetic enhancement of photocatalytic activity is achieved by the slow photon effect and improved separation efficiency of photogenerated charge carriers. The obtained composites could afford very high hydrogen production efficiencies up to 19.67 mmol·g−1·h−1, with an apparent quantum efficiency of 35.9% at 420 nm, which is 4.2 and 23.9 times higher than those of pure Zn0.5Cd0.5S (4.67 mmol·g−1·h−1) and CdS (0.82 mmol·g−1·h−1), respectively. In particular, under Pt-free conditions, an attractive hydrogen production rate (3.23 mmol·g−1·h−1) was achieved, providing a low-cost and high-efficiency strategy to produce hydrogen from water splitting. Moreover, the composites showed excellent stability, and no obvious loss in activity was observed after five cycling tests. [ABSTRACT FROM AUTHOR]

It is known that the low lifetime of photogenerated carriers is the main drawback of elemental photocatalysts. Therefore, a facile and versatile one‐step strategy to simultaneously achieve the oxygen covalent functionalization of amorphous red phosphorus (RP) and in situ modification of CdCO3 is reported. This strategy endows RP with enhanced charge carrier separation ability and photocatalytic activity by coupling band‐gap engineering and heterojunction construction. The as‐prepared nCdCO3/SO‐RP (n=0.1, 0.25, 0.5, 1.0) composites exhibited excellent photocatalytic H2 evolution activity (up to 516.3 μmol g−1 h) from visible‐light‐driven water splitting (λ>400 nm), which is about 17.6 times higher than that of pristine RP. By experimental and theoretical investigations, the roles of surface oxygen covalent functionalization, that is, prolonging the lifetime of photogenerated carriers and inducing the negative shift of the conduction band potential, were studied in detail. Moreover, the charge transfer mechanism of these composites has also been proposed. In addition, these composites are stable and can be reused at least for three times without significant activity loss. This work may provide a good example of how to promote the activity of elemental photocatalysts by decorating their atomic structure. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. Antifibrotic therapies are likely to be a crucial strategy in curbing many fibrosis-related cardiac diseases. In our previous study, an ethyl acetate extract of a traditional Chinese medicine Aristolochia yunnanensis Franch. was found to have a therapeutic effect on myocardial fibrosis in vitro and in vivo. However, the exact chemicals and their mechanisms responsible for the activity of the crude extract have not been illustrated yet. In the current study, 10 sesquiterpenoids (1-10) were isolated from the active extract, and their antifibrotic effects were systematically evaluated in transforming growth factor β 1 (TGFβ1)-stimulated cardiac fibroblasts and NIH3T3 fibrosis models. (+)-Isobicyclogermacrenal (1) and spathulenol (2) were identified as the main active components, being more potent than the well-known natural antifibrotic agent oxymatrine. Compounds 1 and 2 could inhibit the TGFβ1-induced cardiac fibroblasts proliferation and suppress the expression of the fibrosis biomarkers fibronectin and α-smooth muscle actin via down-regulation of their mRNA levels. The mechanism study revealed that 1 and 2 could inhibit the phosphorylation of TGFβ type I receptor, leading to the decrease of the phosphorylation levels of downstream Smad2/3, then consequently blocking the nuclear translocation of Smad2/3 in the TGFβ/Smad signaling pathway. These findings suggest that 1 and 2 may serve as promising natural leads for the development of anticardiac fibrosis drugs. [ABSTRACT FROM AUTHOR]