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Considering that simultaneous detection of xanthine (XA) and hypoxanthine (HXA) has been proved to be a reliable and feasible method for assessing fish freshness, a novel electrochemical sensing platform based on the ZnIn2S4/UiO-66-NH2 modified glassy carbon electrode (GCE) was constructed in this study for XA and HXA determination. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) were performed to exhibit the morphology and structural characteristics of ZnIn2S4/UiO-66-NH2. The Brunauer–Emmett–Teller (BET) displayed that the introduction of UiO-66-NH2 can improve the specific surface area of the hybrid. Besides, the electrochemical sensing performance of ZnIn2S4/UiO-66-NH2 was evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). For simultaneously detecting XA and HXA, the fabricated electrochemical sensor shows wide linear ranges (0.025–40 µM and 0.3–40 µM) with low detection limits (0.0083 µM and 0.1 µM). This sensor also has 96–103% recovery in detecting XA and HXA content in large yellow croaker meat samples, demonstrating a promising application in the marine food industry. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of organic pollution is a vital path to deal with environmental problems. Here, a direct Z-scheme 2D/2D heterojunction of a Fe 3 O 4 /Bi 2 WO 6 photocatalyst is fabricated for the degradation of ciprofloxacin by a self-assembly strategy. Furthermore, to characterize the morphology of the obtained composite photocatalysts, various kinds of characterization methods were employed like XRD, XPS, SEM, and TEM. It is indicated that the flower-like photocatalyst is composed of nanosheets. Comparable photocatalysts were prepared by controlling the hydrothermal temperature and the iron content. In the photocatalytic degradation of ciprofloxacin (CIP) in water, under visible light irradiation, FB-180 (synthesized at 180 °C with 4% iron content) presents approximately 99.7% degradation efficiency in only 15 min. Meanwhile, during photocatalytic degradation reactions, the Fe 3 O 4 /Bi 2 WO 6 heterojunction also displayed excellent stability, which still kept above 90% degradation efficiency after five consecutive cycles. UV-Vis DRS and M-S analyses showed that the Fe 3 O 4 /Bi 2 WO 6 catalyst has a strong visible light absorption capacity and the transfer pathway of photo-induced charge carriers. PL, EIS, and TPR showed that Fe 3 O 4 /Bi 2 WO 6 has an efficient separation and transfer rate of the photo-generated carriers. ESR analysis proved that the superoxide radical ( • O 2 - ) and hydroxyl radical ( • OH) play a major role in the Fe 3 O 4 /Bi 2 WO 6 photocatalytic system. This special 2D/2D heterojunction we proposed may have huge potential for marine pollution treatment by photocatalysis degradation with dramatically boosted activities., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)