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Transition metal selenides are a research hotspot in sodium-ion batteries (SIBs).

Monodisperse FeSe2 microflowers are synthesized by a one-step facile solvothermal method and exhibit excellent electrochemical performance as anode materials for Na-ion batteries.

V-based materials are widely applied as cathode materials for aqueous zinc-ion batteries because the high potential of V5+ provides a thermodynamic basis for the transition of Zn2+. The isotropy of high entropy amorphous vanadium oxide not only avoids the performance degradation caused by the broken crystal structure, but also offers more active sites and improves the solid-state solubility and transfer kinetics of Zn2+. Herein, a high entropy amorphous vanadium oxide@carbon matrix (VxOy@C) was obtained via a simple coprecipitation method. Two electrochemical activation strategies could induce the activation of amorphous VxOy@C as a high-performance cathode material for aqueous zinc-ion batteries (AZIBs). After electrochemical activation, the amorphous VxOy@C exhibited a high specific capacity of 399.1 mA h g−1, high rate capability of 314.1 mA h g−1 at 2.0 A g−1 and excellent cycling stability for up to 300 cycles with a specific capacity retention of 91.8%. It was proven that the amorphous lump of VxOy@C transforms into an amorphous fibrous material accompanied by an increase in the valency of V. With the insertion of Zn2+, the fibrous materials would be reversibly converted into a lamellar structure.

The potential homogeneous assay employing immunomagnetic beads (IMB) has been receiving attention as a screening tool in food-safety control; the method is simple, efficient, and does not require long incubation times or complex separation steps. In this study, a homogeneous immunoassay has been successfully developed and applied in the determination of aflatoxin B1 (AFB1) contamination in agricultural products by coupling IMB and the biotin-streptavidin (BSA) (BSA-IMB) system. Under optimal conditions, the limit of detection (LOD, IC10), half-maximal inhibition concentration (IC50) and detection range (IC20–IC80) of BSA-IMB are 0.00579, 0.573 and 0.0183–17.9 ng mL−1, respectively, for AFB1. The detection of AFB1 by BSA-IMB can be achieved in 40 min (ELISA needs at least 180 min). The cross-reactivities of BSA-IMB with its analogues are negligible (

An indirect competitive enzyme-linked immunosorbent assay (ELISA) for flonicamid was developed based on a polyclonal antibody. 4-Trifluoronicotinic acid (TFNA) was used as flonicamid hapten and conjugated to bovine serum albumin (BSA) to produce an immunogen and ovalbumin (OVA) to produce a coating antigen. Polyclonal antibodies against flonicamid were successfully produced by immunizing New Zealand white rabbits. Under the optimal conditions, the 50% inhibitory concentration (IC50 value) of standard curves was 7.89 mg L−1 and the limit of detection (IC10) was 0.063 mg L−1. There was almost no cross-reactivity of the antibody with three structurally related metabolites, indicating that the antibody had high specificity. The recoveries from spiked water, soil, tomato and apples were in the range of 82.4–113.4% with relative standard deviations of 2.9–10.3%. Moreover, the ELISA for spiked samples showed reliability and high correlation with gas chromatography. These results suggest that the proposed ELISA method has potential application for screening flonicamid in agricultural and environmental samples.