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High entropy alloy nanoparticles (HEA-NPs) are expanding their influence in many fields. To explore the electronic structures in such multielemental systems, HEA-NPs were synthesized on two different carbon substrates through carbothermal shock and in situ reduction methods. The relationship between the apparent core level energy shifts (negative or positive) and the electron density changes among the components of quinary-metal HEA-NPs was investigated by X-ray photoelectron spectroscopy (XPS) analysis and first-principles electronic structure calculations. It was found that Cu displays a negative core level shift while Fe, Co, Mg, Cr, and Mn display a positive core level shift. While experiments show an apparent positive core level shift for Ni, electronic structure calculations reveal that this arises from shifts in the Fermi level and that the electron density redistribution in Ni behaves more like Cu than the other elements. The findings show that the electron density redistribution in the NPs occurs from less electronegative elements to more electronegative ones. This work should guide the design of HEA-NPs to expand their potential applications in mechanical structures, medicine, catalysis, and energy storage/conversion.

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Colloidosomes have attracted considerable attention in recent years because of their potential applications in a range of industries, such as food, bioreactors and medicine. However, traditional polymer shell colloidosomes leak low molecular weight encapsulated materials due to their intrinsic shell permeability. Here, we report aqueous core colloidosomes coated with a gold shell, which make the capsules impermeable. The shells can be ruptured using ultrasound. The gold coated colloidosomes are prepared by making an aqueous core capsule with a polymer shell and then adding HAuCl4, surfactant and l-ascorbic acid to form a second shell. We propose to use the capsules as drug carriers. The gold coated colloidosomes demonstrate a low cytotoxicity and after triggering, both encapsulated doxorubicin and broken gold fragments kill cancer cells. In addition, we set up a targeting model by modifying the gold shell colloidosomes using 4,4'-dithiodibutyric acid and crosslinking them with proteins-rabbit immunoglobulin G (IgG). Label-free surface plasmon resonance was used to test the specific targeting of the functional gold shells with rabbit antigen. The results demonstrate that a new type of functional gold coated colloidosome with non-permeability, ultrasound sensitivity and immunoassay targeting could be applied to many medical applications.

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A facile high‐temperature solution route to a monodisperse core‐shell structure of MnO (core) and MnFe2O4 (shell) (abbreviated as MFO) nanoparticles anchored on reduced graphene oxide (rGO) has been established. Subsequently, MnO@MnFe2O4@rGO nanocomposites are utilized as advanced anode materials for high‐performance Li‐ion batteries. MnO@3MFO@rGO containing 22.5 wt% of the rGO composite (with a 1 : 3 molar ratio of MnO/MFO) as the electrodes delivered a remarkable cycling performance, that is, 587.8 mAh g−1 at a current density of 200 mA g−1 after 200 cycles at ambient temperature with an ultralow capacity fading (0.10 % per cycle). More importantly, the electrodes afforded excellent capacity stability under various operation temperatures (ca. −20 to 70 °C), such as an excellent reversible capacity of 1067 mA h g−1 at a current density of 500 mA g−1 after 300 cycles at 60 °C, and remarkable low‐temperature performance of a reversible capacity of 208.7 mA h g−1 at a current density of 200 mA g−1 at −20 °C. Therefore, MnO@3MFO@rGO nanocomposites are considered as promising battery materials that can be operated in harsh environments.