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A tetragonal Cu2Se film containing a well-aligned nanosheet array with scattered 3D flower-like microstructures on top was synthesized for the first time by a rapid one-step low-energy route, which is beneficial for large scale industrial production due to savings in energy, time and expensive instruments. Phase transformation occurred after scraping the film from the Cu substrate, and heating or grinding the Cu2Se powder in air. The Cu2Se/Cu3Se2 composite containing p-Cu2Se/p-Cu3Se2 heterojunctions was obtained by simply calcining the Cu2Se in air at 300 °C for 3 h. The composite has enhanced gas sensing properties towards acetone gas and a lower band gap energy compared to Cu2Se. [ABSTRACT FROM AUTHOR]

Material synthesis processes involving the bifunctional modulation of an ionic liquid have rarely been reported, and they should be significant to enrich liquid-phase synthesis methods. In this work, through the bifunctional modulation of the ionic liquid [Bmim]Cl, SnSe nanorafts and single-crystal SnSe nanorods with appropriately large diameters and length-to-diameter ratios were successfully fabricated by the solvothermal method. The role of [Bmim]Cl was to template the formation of the 1D assembly and promote the consequent rearrangement, reconstruction, coalescence and fusion of the SnSe nanoparticles in the 1D assembly. When used as photoelectric materials, the SnSe nanorafts and nanorods exhibited much better performance with high switching “ON/OFF” ratios of about 12 and 20, respectively, and they were superior to most of the previously reported SnSe products. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) flower-like Cu2−xSe film with a hexagonal nanosheet hierarchical structure has been synthesized for the first time from a 3D flower-like CuO film precursor through a facile sacrificing template method at room temperature. The product was characterized and its formation mechanism was explored using a series of control experiments combined with crystal structure analysis. The optical property and photodegradation activities of the Cu2−xSe film on three dye solutions were studied. Notably, its antibacterial activities were explored for the first time . The results show that the 3D flower-like Cu2−xSe is assembled from numerous hexagonal nanosheets with thicknesses of about 50 nm. The flower-like Cu2−xSe displays excellent antibacterial activities against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). For the first time, the experimental results confirm that the antibacterial rate depends on the Cu(ii) ion concentration which is closely related to the Cu2−xSe quantity and incubation time. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) hierarchical copper sulfide (CuS) microflowers have been successfully constructed by a facile ionic liquid (1-butyl-3-methylimidazolium chloride, [BMIm]Cl)-assisted solvothermal method at a low temperature (65 °C). Covellite CuS assembled into nanoflakes with a thickness of 8–10 nm and a lateral dimension of about 700 nm was obtained by the decomposition of intermediate complex Cu3(TAA)3Cl3 (thioacetamide, TAA) blocks. The ionic liquid (IL) could serve as a solvent, ligand, and structure-directing agent, which played an important role in the morphologies of Cu3(TAA)3Cl3 and CuS. It is found that CuCl could be interacted with [BMIm]Cl, leading to the formation of [BMIm]CuCl2. Furthermore, the CuS crystal growth along the ＜001＞ direction was inhibited by the absorption of alkylimidazolium rings ([BMIm]+) on the (001) facets of CuS. The morphology and size of CuS were controllable by changing the concentration of [BMIm]Cl. Moreover, 3D hierarchical CuS microflowers used as the photocatalyst showed enhanced visible-light photocatalytic activity for the degradation of methylene blue (MB), due to their large specific surface area, mesoporous structure, and advantageous optical properties. This synthetic method could be expanded to prepare other metal chalcogenides, owing to its simple and safe operation, mild reaction conditions, and low cost. [ABSTRACT FROM AUTHOR]

A series of Fe-doped TiO2 samples with different concentrations of Fe3+ ions annealed at different temperatures were prepared using a sol–gel method. For Fe-doped TiO2, the existing states of Fe3+, the transformation of these existing states and the phase transition are investigated. It is revealed that the existing states of Fe3+ and the transformation of these existing states (substitutional Fe3+, α-Fe2O3 and Fe2TiO5) are closely related to the annealing temperature and the concentration of Fe3+. The anatase–rutile (A–R) transition is promoted by the substitutionally doped Fe in the TiO2 lattice. In addition, the Fe-doped TiO2 with a high calcination temperature (800 °C) and high doping concentration (x ＞ 20) shows obvious ultrasonic piezoelectric catalytic activity for the reduction of CO2 to CH4. This work may be useful in understanding the doping mechanisms of Fe-doped TiO2, and the fabrication of new catalytic materials. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) hierarchical copper sulfide (CuS) microflowers have been successfully constructed by a facile ionic liquid (1-butyl-3-methylimidazolium chloride, [BMIm]Cl)-assisted solvothermal method at a low temperature (65 °C). Covellite CuS assembled into nanoflakes with a thickness of 8–10 nm and a lateral dimension of about 700 nm was obtained by the decomposition of intermediate complex Cu3(TAA)3Cl3 (thioacetamide, TAA) blocks. The ionic liquid (IL) could serve as a solvent, ligand, and structure-directing agent, which played an important role in the morphologies of Cu3(TAA)3Cl3 and CuS. It is found that CuCl could be interacted with [BMIm]Cl, leading to the formation of [BMIm]CuCl2. Furthermore, the CuS crystal growth along the ＜001＞ direction was inhibited by the absorption of alkylimidazolium rings ([BMIm]+) on the (001) facets of CuS. The morphology and size of CuS were controllable by changing the concentration of [BMIm]Cl. Moreover, 3D hierarchical CuS microflowers used as the photocatalyst showed enhanced visible-light photocatalytic activity for the degradation of methylene blue (MB), due to their large specific surface area, mesoporous structure, and advantageous optical properties. This synthetic method could be expanded to prepare other metal chalcogenides, owing to its simple and safe operation, mild reaction conditions, and low cost. [ABSTRACT FROM AUTHOR]

A series of Zn doped TiO2 is prepared via a sol–gel method by changing the concentration of Zn ions and calcination temperature. To investigate the existing states of introduced Zn, the transformation of existing states and the phase transition for the Zn doped TiO2 samples, high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques are applied. The existing states of Zn2+ ions and the transformation of existing states (O–Zn–Cl and ZnTiO3) in Zn doped TiO2 are closely related to the calcination temperature and concentration of introduced Zn ions, as well as the phase transition temperature from anatase to rutile. This work can be helpful for a better realization about the doping mechanism of Zn2+ ions in Zn doped TiO2. [ABSTRACT FROM AUTHOR]

Novel α-Ag3VO4 nanostructures have been successfully synthesized via a facile and repeatable precipitation method by using n-BA as precipitant and complexing agent. Photocatalytic property tests for decomposition of RhB demonstrate that the as-prepared nanostructures have enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]

Morphology-controllable ZnO rings with high crystallinity were synthesized by a simple hydrothermal approach, using ionic liquid (through surface energy conditioning) as a stabilizing agent or template. The growth mechanism of these ring-like ZnO crystals was explored based on first-principles calculations and a series of controlled experiments where the concentration of the ionic liquid 1-propyl-3-methylimidazolium bromide ([C3mim]Br) was tuned. With the increase of the concentration of [C3mim]Br, the aspect ratio of ZnO product increases, and the morphology changes from ring to tube. FTIR and theoretical calculations indicate that [C3mim]Br prefers to adsorb on the ZnO (101̅0) facets, which lowers the surface energy so as to protect the lateral facets from growing too fast to vanish and result in the formation of disk-like structures. Furthermore, the relatively high density of the defects and dislocations on the exposed (0001̅) facet at the center of ZnO disks results in a higher etching rate of (0001̅) facet by H+, driven by the reduction of strain energy associated with dislocations. Therefore, the selective etching of ZnO disks leads to formation of ring-like structure for final products. With the increase of the concentration of [C3mim]Br, the selective adsorption of [C3mim]Br will also promote the growth along the [0001] direction to form a tube-like structure. In addition, the photoluminescence spectra reveal that the as-prepared ZnO rings exhibit blue emission related to their oxygen vacancy as well as various other barely avoidable impurities and defects. [ABSTRACT FROM AUTHOR]

Morphology control of bismuth sulfide (Bi2S3) nanostructures, from one-dimensional nanorods with various aspect ratios, to various kinds of two-dimensional nanofabrics (dense nanofabrics and spark nanofabrics) to three-dimensional urchin-like microspheres and crossed nanofabrics, has been achieved viaan ionic liquids-assisted hydrothermal route, by adjusting the active state of the BiOCl, the characteristics and concentration of the ionic liquid used and the reaction temperature. Reasonable growth mechanisms for the Bi2S3with different morphologies are proposed, based on active state of the intermediate BiOCl, characteristics of the ionic liquids used and the crystal growth habits of Bi2S3. More importantly, we introduce the concept of two different states of the intermediate BiOCl (active BiOCl and inert BiOCl) to explain the growth mechanisms of nanofabrics, nanorods and urchin-like microspheres, from different crystal growth processes. Moreover, electrochemical measurements demonstrate that Bi2S3nanofabrics and urchin-like microspheres possess higher initial Li intercalation capacity than graphitic materials (372 mA h g−1), and their cyclic performances are highly dependent on their morphologies. [ABSTRACT FROM AUTHOR]