Covalently crosslinked graphene oxide papers (GOPs) with enhanced mechanical properties are prepared by a strategy involving crosslinking by means of intercalated polymers. The strength and modulus of the crosslinked GOPs increase by 115% and 550%, respectively, compared to the pristine GOPs. These results broaden the potential applications of graphene, and the crosslinking strategy will open the door to the assembly of other nanometer-scale materials.

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Due to its excellent flexibility, graphene has an important application prospect in epidermal electronic sensors. However, there are drawbacks in current devices, such as sensitivity, range, lamination, and artistry. In this work, we have demonstrated a multilayer graphene epidermal electronic skin based on laser scribing graphene, whose patterns are programmable. A process has been developed to remove the unreduced graphene oxide. This method makes the epidermal electronic skin not only transferable to butterflies, human bodies, and any other objects inseparably and elegantly, merely with the assistance of water, but also have better sensitivity and stability. Therefore, pattern electronic skin could attach to every object like artwork. When packed in Ecoflex, electronic skin exhibits excellent performance, including ultrahigh sensitivity (gauge factor up to 673), large strain range (as high as 10%), and long-term stability. Therefore, many subtle physiological signals can be detected based on epidermal electronic skin with a single graphene line. Electronic skin with multiple graphene lines is employed to detect large-range human motion. To provide a deeper understanding of the resistance variation mechanism, a physical model is established to explain the relationship between the crack directions and electrical characteristics. These results show that graphene epidermal electronic skin has huge potential in health care and intelligent systems.

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The electrochemical nitrogen reduction reaction (NRR) is a very efficient method for sustainable NH3 production, but it requires effective catalysts to expedite the NRR kinetics and inhibit the concomitant hydrogen evolution reaction (HER). Two-dimensional (2D)/2D interface engineering is an effective method to design powerful catalysts due to intimate face-to-face contact of two 2D materials that facilitates the strong interfacial electronic interactions. Herein, we explored a 2D/2D MoS2/C3N4 heterostructure as an active and stable NRR catalyst. MoS2/C3N4 exhibited a conspicuously improved NRR performance with an NH3 yield of 18.5 μg h–1 mg–1 and a high Faradaic efficiency (FE) of 17.8% at −0.3 V, far better than those of the individual MoS2 or C3N4 component. Density functional theory calculations revealed that the interfacial charge transport from C3N4 to MoS2 could enhance the NRR activity of MoS2/C3N4 by promoting the stabilization of the key intermediate *N2H on Mo edge sites of MoS2 and concurrently decreasing the reaction energy barrier. Meanwhile, MoS2/C3N4 rendered a more favorable *H adsorption free energy on S edge sites than on Mo edge sites of MoS2, thereby protecting the NRR-active Mo edge sites from the competing HER and leading to a high FE.

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.201905842. Rechargeable Zn/MnO 2 batteries using mild aqueous electrolytes are attracting extensive attention due to their low cost, high safety, and environmental friendliness. However, the charge-storage mechanism involved remains a topic of controversy so far. Also, the practical energy density and cycling stability are still major issues for their applications. Herein, a free-standing α-MnO 2 cathode for aqueous zinc-ion batteries (ZIBs) is directly constructed with ultralong nanowires, leading to a rather high energy density of 384 mWh g −1 for the entire electrode. Greatly, the H + /Zn 2+ coinsertion mechanism of α-MnO 2 cathode for aqueous ZIBs is confirmed by a combined analysis of in situ X-ray diffractometry, ex situ transmission electron microscopy, and electrochemical methods. More interestingly, the Zn 2+ -insertion is found to be less reversible than H + -insertion in view of the dramatic capacity fading occurring in the Zn 2+ -insertion step, which is further evidenced by the discovery of an irreversible ZnMn 2 O 4 layer at the surface of α-MnO 2 . Hence, the H + -insertion process actually plays a crucial role in maintaining the cycling performance of the aqueous Zn/α-MnO 2 battery. This work is believed to provide an insight into the charge-storage mechanism of α-MnO 2 in aqueous systems and paves the way for designing aqueous ZIBs with high energy density and long-term cycling ability. www.advancedsciencenews.com

A strategy to prepare doxorubicin-loaded magnetic silk fibroin nanoparticles is presented. The nanoparticles serve as a nanometer-scale drug-delivery system in the chemotherapy of multidrug-resistant cancer under the guidance of a magnetic field. The magnetic tumor-targeting ability broadens the range of biomedical applications of silk fibroin, and the nanoparticle-assisted preparation strategy is useful for the advancement of other biomacromolecule-based materials.

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