Nanocomposites with constituent sizes of <50nm are considered as a promising approach to enhance the figure of merit of bulk thermoelectric materials. A simple route involving hydrothermal synthesis and hot pressing was used in this work to prepare Bi2Te3∕Sb2Te3 bulk nanocomposites. It is shown that the composites have a laminated structure composed of Bi2Te3 and Sb2Te3 nanolayers with the thickness varying alternately between 5 and 50nm. The transport measurements indicate that the nanoscale laminated structure improves the thermoelectric performance with the maximal dimensionless figure of merit of 1.47 for the nanocomposite hot pressed from Bi2Te3 and Sb2Te3 nanopowders.

No abstract

No abstract

No abstract

Novel TiO2/Sn3O4 heterostructure photocatalysts were ingeniously synthesized via a scalable two-step method. The impressive photocatalytic abilities of the TiO2/Sn3O4 sphere nanocomposites were validated by the degradation test of methyl orange and •OH trapping photoluminescence experiments under ultraviolet (UV) and visible light irradiation, respectively. Especially under the visible light, the TiO2/Sn3O4 nanocomposites demonstrated a superb photocatalytic activity, with 81.2% of methyl orange (MO) decomposed at 30 min after irradiation, which greatly exceeded that of the P25 (13.4%), TiO2 (0.5%) and pure Sn3O4 (59.1%) nanostructures. This enhanced photocatalytic performance could be attributed to the mesopore induced by the monodispersed TiO2 cores that supply sufficient surface areas and accessibility to reactant molecules. This exquisite hetero-architecture facilitates extended UV-visible absorption and efficient photoexcited charge carrier separation.

Due to the metastable property and arduous preparation, to control the size and shape of intermediate Sn 3 O 4 nanocrystals to tune functional properties still poses great challenge, and the physical and chemical properties are not fully investigated. Here, we report a simple one-pot template-free hydrothermal route to fabricate Sn 3 O 4 flower-like hierarchical structures self-assembled by aligned high-density nanoslices. In order to explore the growth mechanism, a series of samples with various hydrothermal time were prepared and examined by FESEM and Raman. Results show that the hydrothermal time influences the phases and morphology of the final products. Particularly, a sensor based on these Sn 3 O 4 was implemented to investigate the potential of Sn 3 O 4 for the ethanol detection, revealing that this material reacts to ethanol in a linear way with high response yet at lower temperature (190 ∘ C) than that of the well-known SnO 2 . Also, this intermediate tin oxide with rational control over dimension and morphology provides new opportunities for practical applications in gas sensing towards other reducing gases.

No abstract

The thermodynamic properties of ternary Mg2BIV (BIV = Si, Ge, Sn) solid solutions were first calculated by the ab‐initio density functional method. The results showed that there exist composition regions with d2G /dx2 < 0 in Mg2Si1–x Snx and Mg2Ge1–x Snx systems, implying the possibility of spinodal decomposition of the pseudobinary solid solutions. It is suggested that the spinodal decomposition would be a potential way to obtain Mg2BIV based bulk in‐situ nanocomposites with reduced grain sizes and enhanced phonon scattering, and hence an improved thermoelectric figure of merit. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)