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In peroxides-based advanced oxidation technologies (AOPs) using Fe-based catalysts, the low efficiency of Fe-ions cycling hinders their industrial applications. Recently, MoS 2 has been validated to be a promising co-catalyst that can effectively promote the dynamic cycling of Fe-ions during the reaction. However, the activities of the reported MoS 2 -loaded Fe-based catalysts still decreased significantly after 3–5 cycling reactions, so it is necessary to develop a catalyst with high activity and stability. A series of MoS 2 @Fe 3 O 4 - x (MF- x) catalysts were successfully constructed to trigger peroxymonosulfate (PMS) to eliminate the refractory organics. Ultrathin MoS 2 nanosheets (∼ 5.7 nm) were uniformly and firmly coated on the surface of Fe 3 O 4 nanoparticles via Fe–S bridging interaction. Pure MoS 2 made little contribution to the climbazole (CBZ) degradation. Compared to the Fe 3 O 4 /PMS system, the adsorption and degradation efficiencies of the CBZ by MF- x /PMS system were improved by 7.5 and 4 times, respectively. The FeII/FeIII and MoIV/MoVI redox cycles on the MF- x surface could interact and work in synergy during the catalytic activation of PMS to degrade pollutants. MF-0.23 was an effective and stable catalyst for application over a wide pH range (2.0–9.8). Moreover, it efficiently dealt with other representative refractory contaminants with different pKa values, such as fluconazole (FZ), phenol, and rhodamine B (RhB). The primary active free radicals in MF-0.23/PMS system were detected to be O 2 •– and SO 4 •–. Specifically, the generated O 2 •– not only participated in the degradation of contaminants but also contributed to the MoIV regeneration. With outstanding catalytic activity, broad applicability, excellent reusability, and long-term stability, the MoS 2 nanosheet-wrapped Fe 3 O 4 nanocrystals should be an ideal heterogeneous catalyst for PMS-based AOPs. [Display omitted] • MoS 2 nanosheet-wrapped Fe 3 O 4 nanocrystals were successfully fabricated. • MF- x showed effective and stable activity in treating refractory contaminants. • MoIV in MoS 2 can effectively promote the FeII/FeIII cycle. • O 2 •– and SO 4 •− were the predominant active oxygen species in the reaction system. • MF- x has excellent potential to be used in environmental remediation. [ABSTRACT FROM AUTHOR]

• A novel MIP-Fe 3 O 4 -NCs with specific recognition sites to BPA was fabricated. • The MIP-Fe 3 O 4 -NCs/GCE could promote the cathodic ECL of luminol and specifically rebind BPA. • The ECL quenching property of MIP-Fe 3 O 4 -NCs was the electron transfer hindrance after BPA adding. • The MIECL sensor for BPA determination in seawater and fish samples were developed. A highly selective molecularly imprinted electrochemiluminescence (MIECL) sensor based on molecularly imprinted Fe 3 O 4 nanocrystals (MIP-Fe 3 O 4 /NCs) and luminol was developed for bisphenol A (BPA) determination. MIP-Fe 3 O 4 -NCs were synthesized and immobilized on the glassy carbon electrode (GCE) surface to fabricate the electrogenerated chemiluminescence (ECL) system. The GCE modified with MIP-Fe 3 O 4 -NCs could greatly promote the cathodic ECL of luminol. After incubation with the BPA solution, the imprinting sites on the surface of MIP-Fe 3 O 4 -NCs could specifically rebind BPA, resulting in selective and sensitive ECL quenching by hindering electron transfer capability. Under optimal conditions, the relative ECL intensities were proportional to the logarithm of BPA concentration ranging from 0.002 μg/L to 5.0 × 103 μg/L at a limit of detection of 2.0 × 10−4 μg/L. Satisfactory recoveries of 93.5 %–98.3 % were obtained in fish and seawater samples at a relative standard deviation of <6.1 %. The proposed MIECL sensor displayed good selectivity, high sensitivity, and excellent accuracy and precision. The results demonstrated the potential application of the MIECL sensor for BPA analysis in actual samples and for pollutant analysis. [ABSTRACT FROM AUTHOR]

• Nonviral gene vector with folate/magnetism targeting based on hyperbranched polymer. • FA-PEG-HPEI as nanoreactors to prepare superparamagnetic Fe 3 O 4 nanocrystals. • Fe 3 O 4 /FA-PEG-HPEI have higher luciferase expression level than HPEI. A new strategy for in situ preparation of non-viral gene vectors with folate/magnetism dual targeting based on hyperbranched polymers has been described. Folate-PEG-grafted-hyperbranched poly(ethylenimine)s (FA-PEG-HPEI) were synthesized and used as nanoreactors to prepare monodisperse Fe 3 O 4 nanocrystals (NCs). The FA-PEG-HPEI had FA targeting groups, low cytotoxicity and ideal gene transfection performance, while Fe 3 O 4 NCs had superparamagnetic property, thus the resulting Fe 3 O 4 /FA-PEG-HPEI nanocomposites integrated the properties of FA-PEG-HPEI and Fe 3 O 4 NCs together. As expected, the Fe 3 O 4 /FA-PEG-HPEI nanocomposites as non-viral gene vectors with folate/magnetism dual targeting had improved luciferase expression level in HEK 293T and Hela cells under a magnetic gradient field. The luciferase expression level mediated by Fe 3 O 4 /FA-PEG-HPEI nanocomposites in HEK 293T and Hela cells under a magnetic gradient field were 21 and 29 fold of that of standard HPEI transfection, respectively. [ABSTRACT FROM AUTHOR]

• The Fe 3 O 4 nanocrystals are well-distributed between Ti 3 C 2 interlayers. • The 2D confinement effects stabilize the hybrids with high exposure of active sites. • The Fe 3 O 4 @Ti 3 C 2 hybrids possess a rapid and stable charge/discharge capability. Balancing energy density and charging rate has been identified as a great challenge for Li-ion batteries (LIBs), which mainly hinges on developing high-performance electrode materials. Herein, we have developed novel Fe 3 O 4 @Ti 3 C 2 hybrids, in which the Fe 3 O 4 nanocrystals are well-anchored between Ti 3 C 2 interlayers with the assistance of the synergistic effects of 2D physical confinement and Ti O Fe covalent bonds. Such structural design can address the dispersion and volume change of nanocrystals during continuous charge/discharge with the enhancement of structural stability and the exposure of abundant active sites for each component. Meantime, the charge polarization caused by the Ti O Fe covalent bonds greatly accelerates the lithiation reaction kinetics and electrons transfer. These advantages endow the Fe 3 O 4 @Ti 3 C 2 hybrids with a very high specific capacity of 1172 mAh g−1 and a rapid charging capability of 366 mAh g−1 in 66 s. A 90% capacity retention can be maintained even through 1000 cycles at 5 A g−1. More impressively, we can also achieve a free-standing electrode by a simple vacuum filtering, exhibiting a high areal capacity of 4.2 mAh cm−2 at 4.4 mg cm−2 almost without sacrificing gravimetric capacity. The present 2D confined strategy provides a new notion to construct satisfactory electrodes for energy storage. [ABSTRACT FROM AUTHOR]