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Carbon quantum dots/TiO2 nanotubes composites were prepared by a simple technical route through which TiO2 nanotubes prepared by electrospinning were dispersed in carbon quantum dots solution, and dried at 80 °C. The results indicated that the TiO2 nanotubes composites were combined with the carbon quantum dots. The photocatalytic activity of the carbon quantum dots/TiO2 nanotubes composites was investigated by the degradation of rhodamine B under visible light irradiation, and it was demonstrated to be significantly enhanced compared with that of pure TiO2 nanotubes. Through analysis, this enhancement of visible light photocatalytic activity was attributed to the carbon quantum dots with the unique up-converted photoluminescence behavior. [ABSTRACT FROM AUTHOR]

Highly photoluminescent ZnSe/Au nanocomposites have been prepared via a simple low-temperature-aqueous synthesis and direct coupling approach. The mechanism of surface plasmons enhanced photoluminescence of ZnSe/Au nanocomposites is investigated. Furthermore, due to high photostability and biocompatibility, the as-prepared ZnSe/Au nanocomposites are demonstrated as excellent probes in cellular imaging. [ABSTRACT FROM AUTHOR]

Abstract: A low-temperature hydrothermal method was developed to synthesize urchinlike γ-MnO2 nanostructures. Time-dependent evolutions of morphology and crystallinity were investigated to explore the growth mechanism of the γ-MnO2 urchins. The results show that the growth process of the γ-MnO2 urchins occurs in two main stages, which are the generation of γ-MnO2 microspheres and the following epitaxial growth of γ-MnO2 nanoneedles on the surface of the initial microspheres. Microwave absorption properties of the urchinlike γ-MnO2 nanostructures were studied in terms of complex permittivity and permeability. An effective absorption bandwidth (reflection loss lower than −10dB) of 8.8GHz was achieved from the γ-MnO2/paraffin wax composite. [Copyright &y& Elsevier]

Rechargeable aqueous zinc ion batteries (AZIBs) have gained considerable attention owing to their low cost and high safety, but dendrite growth, low plating/stripping efficiency, surface passivation, and self-erosion of the Zn metal anode are hindering their application. Herein, a one-step in situ molecular engineering strategy for the simultaneous construction of hierarchical MoS 2 double-layer nanotubes (MoS 2 -DLTs) with expanded layer-spacing, oxygen doping, structural defects, and an abundant 1T-phase is proposed, which are designed as an intercalation-type anode for "rocking-chair" AZIBs, avoiding the Zn anode issues and therefore displaying a long cycling life. Benefiting from the structural optimization and molecular engineering, the Zn 2+ diffusion efficiency and interface reaction kinetics of MoS 2 -DLTs are enhanced. When coupled with a homemade ZnMn 2 O 4 cathode, the assembled MoS 2 -DLTs//ZnMn 2 O 4 full battery exhibited impressive cycling stability with a capacity retention of 86.6% over 10 000 cycles under 1 A g -1 anode , outperforming most of the reported "rocking-chair" AZIBs. The Zn 2+ /H + cointercalation mechanism of MoS 2 -DLTs is investigated by synchrotron in situ powder X-ray diffraction and multiple ex situ characterizations. This research demonstrates the feasibility of MoS 2 for Zn-storage anodes that can be used to construct reliable aqueous full batteries.

Molybdenum disulfide (MoS 2 ) nanosheets are promising candidates as earth-abundant and low-cost catalyst for hydrogen evolution reaction (HER). Nevertheless, compared with the benchmark Pt/C catalyst, the application of MoS 2 nanosheets is limited to its relatively low catalytic activity, especially in alkaline environments. Here, we developed a dual-cation doping strategy to improve the alkaline HER performance of MoS 2 nanosheets. The designed Ni, Co co-doped MoS 2 nanosheets can promote the tandem HER steps simultaneously, thus leading to a much enhanced catalytic activity in alkaline solution. Density functional theory calculations revealed the individual roles of Ni and Co dopants in the catalytic process. The doped Ni is uncovered to be the active site for the initial water-cleaving step, while the Co dopant is conducive to the H desorbing by regulating the electronic structure of neighboring edge-S in MoS 2 . The synergistic effect resulted by the dual-cation doping thus facilitates the tandem HER steps, providing an effective route to raise the catalytic performance of MoS 2 materials in alkaline solution., (© 2021 IOP Publishing Ltd.)

Three dimensional (3D) hierarchical nanostructures are expected to provide enhanced microwave absorption properties for nanomaterials. In this report we prepared hollow urchinlike alpha-MnO2 nanostructures and dispersed alpha-MnO2 nanorods via a facile hydrothermal method. The complex permittivity and permeability of the hollow alpha-MnO2 nanourchins/paraffin wax composites with different manganese dioxide loadings were investigated in the range of 2-18 GHz, based on which the corresponding reflection loss were simulated. A minimum reflection loss of -36 dB was obtained from the composites with 50 wt% MnO2 nanostructures. Furthermore, the microwave absorption properties of dispersed alpha-MnO2 nanorods were studied for comparison, which indicate the unique morphology of the hollow urchinlike nanostructures is of significant effect to their microwave absorption properties.