A convenient hydrothermal intercalation/exfoliation method for large-scale manufacturing of bismuth telluride (Bi 2 Te 3 ) nanosheets is reported here. Lithium cations can be intercalated between the layers of Bi 2 Te 3 using the reducing power of ethylene glycol in the common hydrothermal process, and high quality Bi 2 Te 3 nanosheets with thickness down to only 3-4 nm are obtained by removing lithium in the following exfoliating process. Scanning electron microscopy, transmission electron microscopy and Raman spectrum characterizations confirm that the high yield of Bi 2 Te 3 nanosheets with good quality were successfully achieved and the sizes of the immense nanosheets reached 200 nm width and 1 mm length. This hydrothermal intercalation/exfoliation method is general, as it has been extended to other layered materials, such as Bi 2 Se 3 and MoS 2 . Our results suggest a simple route for the large-scale production of thin and flat Bi 2 Te 3 nanosheets, which may be beneficial to further electronic and spintronics applications.

Rational nanoscale surface engineering of electroactive nanoarchitecture is highly desirable, since it can both secure high surface‐controlled energy storage and sustain the structural integrity for long‐time and high‐rate cycling. Herein, ultrasmall MoS2 quantum dots (QDs) are exploited as surface sensitizers to boost the electrochemical properties of Li4Ti5O12 (LTO). The LTO/MoS2 composite is prepared by anchoring 2D LTO nanosheets with ultrasmall MoS2 QDs using a simple and effective assembly technique. Impressively, such 0D/2D heterostructure composites possess enhanced surface‐controlled Li/Na storage behavior. This unprecedented Li/Na storage process provides a LTO/MoS2 composite with outstanding Li/Na storage properties, such as high capacity and high‐rate capability as well as long‐term cycling stability. As anodes in Li‐ion batteries, the materials have a stable specific capacity of 170 mAhg−1 after 20 cycles and are able to retain 94.1% of this capacity after 1000 cycles, i.e., 160 mAhg−1, at a high rate of 10 C. Due to these impressice performance, the presented 0D/2D heterostructure has great potential in high‐performance LIBs and sodium‐ion batteries.

A novel composite of reduced graphene oxide (RGO) and FeS 2 microparticles self-assembled from small size cubes as a high-performance anode material for lithium-ion batteries (LIBs) has been prepared via a facile one-pot hydrothermal method. The prepared composite shows interconnected networks of reduced graphene oxide sheets and well-dispersed FeS 2 microparticles which were composed of smallsize cubic FeS 2 crystals. The composite not only provides a high contact area between the electrolyte and the electrode, favorable diffusion kinetics for both electrons and lithium ions, but also provides the protection against the volume changes of electroactive FeS 2 materials and excellent electrical conductivity of the overall electrode during electrochemical processes as well as an enhanced synergistic effect between cubic FeS 2 and RGO. As an anode material for LIBs, it exhibits a very large initial reversible capacity of 1147 mA h g À1 at a current rate of 100 mA h g À1 and maintains 1001.41 mA h g À1 over 60 cycles, which is much higher than that of the theoretical capacity of graphite (372 mA h g À1 ) and indicates high stability. The results demonstrate that the composite can be a promising candidate for electroactive materials in LIBs.

We theoretically investigate the phonon scattering by vacancies, including the impacts of missing mass and linkages () and the variation of the force constant of bonds associated with vacancies () by the bond-order-length-strength correlation mechanism. We find that in bulk crystals, the phonon scattering rate due to change of force constant is about three orders of magnitude lower than that due to missing mass and linkages . In contrast to the negligible in bulk materials, in two-dimensional materials can be 3–10 folds larger than . Incorporating this phonon scattering mechanism to the Boltzmann transport equation derives that the thermal conductivity of vacancy defective graphene is severely reduced even for very low vacancy density. High-frequency phonon contribution to thermal conductivity reduces substantially. Our findings are helpful not only to understand the severe suppression of thermal conductivity by vacancies, but also to manipulate thermal conductivity in two-dimensional materials by phononic engineering.

Here, a graphene-based aerogel embedded with two types of functional nanoparticles shaped in a three-dimensional (3D) cylindrical architecture was prepared by a facile one-pot hydrothermal process. During the hydrothermal reaction, the uniformly dispersed TiO2 (P25) and CdS nanoparticles were loaded on the graphene sheets, and the resulting composites were self-assembled into a 3D interconnected network. It is shown that the graphene-based hydrogel and aerogel are appropriate and robust hosts for anchoring different functional nanostructured particles. The outstanding synergistic effect of this ternary graphene-based nanocomposite aerogel is also proved by the excellent photoelectrochemical activity of the as-prepared novel nanocomposite (CdS/P25/graphene) aerogel. As a new photocatalyst, the CdS/P25/graphene aerogel exhibits enhanced light absorption, improved photocurrent, extremely efficient charge separation properties, and superior durability. These excellent properties indicate that the as-prepared CdS/P25/graphene aerogel may have a great potential application in photoelectrochemical hydrogen production from water reduction under sunlight. More importantly, in this study, a significant and pragmatic consideration of integrating multifarious functional nanoobjects into the 3D graphene-based aerogel has been clearly proposed. This could provide new insights into the preparation of functional nanocomposites and facilitate their applications in related areas.

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Hexagonal Yb3+-Ho3+-Tm3+ triply doped NaYF4 nanorods were synthesized via a hydrothermal method using oleic acid as a stabilizing agent. White up-conversion (UC) luminescence consisting of the blue UC radiations at 450 and 475 nm corresponding to the 1 D 2 → 3 F 4 and 1 G 4 → 3 H 6 transitions of Tm3+ ion, green at 545 nm to the 5 S 2 /5 F 4 → 5 I 8 transition of Ho3+ ions and red at 695 nm to the 3 F 3 → 3 H 6 of Tm3+ ion and at 650 nm including both the 5 F 5 → 5 I 8 transition of the Ho3+ ion and the 3 F 2 → 3 H 6 transition of Tm3+ ion, was observed in the as-prepared nanorods under the excitation of a 980 nm diode laser. The calculated color coordinates display that with the increase of pump power densities, the tendency of white color output turns toward the blue region, revealing that white UC light can be fine-tuned in a wide range of pump power densities. On the basis of spectral and pump power dependence analyses, the UC mechanisms for the fine-tuned white output were discussed in detail.

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