Developing low-cost, efficient, and bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an appealing yet challenging task. Herein, for the first time, a NiS microsphere film was grown in situ on Ni foam (NiS/Ni foam) via a sulfurization reaction as an efficient bifunctional electrocatalyst for overall water splitting with superior activity and good durability. This NiS/Ni foam electrode delivers 20 mA cm(-2) at an overpotential of 158 mV for the HER and 50 mA cm(-2) at an overpotential of 335 mV for the OER in 1.0 M KOH. This bifunctional electrode also enables a high-efficiency alkaline water electrolyzer with 10 mA cm(-2) at a cell voltage of only 1.64 V, which could be promising in water splitting devices for large-scale hydrogen production.

A prerequisite for exploiting most proposed applications for MoS2 is the availability of water-dispersible functionalized MoS2 nanosheets in large quantities. Here we report one-step synthesis and surface functionalization of MoS2 nanosheets by a facile ionic liquid assisted grinding method in the presence of chitosan. The selected ionic liquid with suitable surface energy could efficiently overcome the van der Waals force between the MoS2 layers. Meanwhile, chitosan molecules bind to the plane of MoS2 sheets non-covalently, which prevents the reassembling of exfoliated MoS2 sheets and facilitates the exfoliation progress. The obtained chitosan functionalized MoS2 nanosheets possess favorable stability and biocompatibility, which renders them as promising and biocompatible near-infrared agents for photothermal ablation of cancer. This contribution provides a facile way for the green, one-step and large-scale synthesis of advanced functional MoS2 materials.

Biologically, MoS2-based nanostructures have been intensely applied for the photothermal therapy of cancer, but rarely for antibacterial uses. In this contribution, a multifunctional chitosan (CS) functionalized magnetic MoS2 (abbreviated to CFM) was constructed to nonspecifically combat bacterial infection by integrating bacterial conjugation and enrichment, and NIR-triggered photothermal sterilization. Owing to the abundant introduced amino groups, the CFM complex offers a significantly enhanced conjugation efficiency without obvious specificity towards both Gram-positive and -negative bacteria compared to amino-free magnetic MoS2. The magnetic properties of CFM obtained from iron oxide facilitate the enrichment of a CFM-bacteria conjugate, improving the photothermal efficiency of CFM as a photothermal antibacterial agent. Specifically, after being trapped together with bacteria cells, CFM shows an enhanced in vitro photothermal sterilization ability. In vivo S. aureus-induced abscess treatment studies show faster healing when CFM is used as subcutaneous nano-localized heating sources with the assistance of an external magnet to concentrate the CFM-bacteria conjugate. This work establishes an innovative solution and a novel antimicrobial agent for combating bacterial infections without the use of antibiotics, which may open a new area of application and research for MoS2-based nanostructures.

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Oxygen evolution reaction (OER) plays a key role in various energy conversion and storage technologies, such as water electrolysis, regenerative fuel cells, and rechargeable metal-air batteries. However, the slow kinetics of OER limit the performance and commercialization of such devices. Herein, we report on NiFe LDH@Au hybrid nanoarrays on Ni foam for much enhanced OER. By hybridization of electronegative Au and NiFe LDH with intrinsic remarkable OER catalytic activity, this modular electrode could drive an overall ultrahigh-performance and robust OER in base with the demand of overpotentials of only 221, 235, and 270 mV to afford 50, 100, and 500 mA cm, respectively. Also, it exhibits superior catalytic activity and durability toward OER in 30 wt % KOH.