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By a facile water evaporation process without adding any directing agent, Cu2‐xSe nanowire bundles with diameters of 100–300 nm and lengths up to hundreds of micrometers, which comprise crystalline nanowires with diameters of 5–8 nm, are obtained. Experiments reveal the initial formation/stacking of CuSe nanoplates and the subsequent transformation to the Cu2‐xSe nanowire bundles. A water‐evaporation‐induced self‐assembly (WEISA) mechanism is proposed, which highlights the driving force of evaporation in promoting the nanoplate stacking, CuSe‐to‐Cu2‐xSe transformation and the growth/bundling of the Cu2‐xSe nanowires. The simplicity, benignancy, scalability, and high‐yield of the synthesis of this important nanowire material herald its numerous applications. As one example, the use of the Cu2‐xSe nanowire bundles as a photoluminescence‐type sensor of humidity is demonstrated, which shows good sensitivity, ideal linearity, quick response/recovery and long lifetime in a very wide humidity range at room temperature.

Assembling complex nanostructures on functional substrates such as electrodes promises new multi‐functional interfaces with synergetic properties capable of integration into larger‐scale devices. Here, we report a microemulsion‐mediated process for the preparation of CuO/Cu electrodes comprising a surface layer of a densely packed array of unusual cog‐shaped CuO microparticles with hierarchical nanofilament‐based superstructure and enhanced electrochemical performance in lithium‐ion batteries. The CuO particles are produced by thermolysis of Cu(OH)2 micro‐cog precursors that spontaneously assemble on the copper substrate when the metal foil is treated with a reactive oil‐based microemulsion containing nanometer‐scale aqueous droplets. The formation of the hierarchical superstructure improves the coulombic efficiency, specific capacity, and cycling performance compared with anodes based on CuO nanorods or polymer‐blended commercial CuO/C black powders, and the values for the initial discharge capacity (1052 mA h g−1) and reversible capacity (810 m A h g−1) are higher than most copper oxide materials used in lithium‐ion batteries. The results indicate that a fabrication strategy based on self‐assembly within confined reaction media, rather than direct synthesis in bulk solution, offers a new approach to the design of electrode surface structures for potential development in a wide range of materials applications.

This paper reports the synthesis of Co 3 O 4 −reduced graphene oxide (rGO) hybrids and the catalytic performance in heterogeneous activation of peroxymonosulfate (PMS) for the decomposition of phenol. The surface morphologies and structures of the Co 3 O 4 −rGO hybrids were investigated by field emission scanning electron microscopy (SEM), energydispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Through an in situ chemical deposition and reduction, Co 3 O 4 −rGO hybrids with Co 3 O 4 nanoparticles at an average size of 33 nm were produced. Catalytic testing showed that 20 mg/L of phenol could be completely oxidized in 20 min at 25 °C on Co 3 O 4 −rGO hybrids, which is mostly attributed to the generation of sulfate radicals through Co 3 O 4 -mediated activation of PMS. Phenol oxidation was fitted by a pseudo-zero-order kinetic model. The rate constant was found to increase with increasing temperature and PMS dosage, but to decrease with increasing initial phenol concentration. The combination of Co 3 O 4 nanoparticles with graphene sheets leads to much higher catalytic activity than pure Co 3 O 4 . rGO plays an important role in Co 3 O 4 dispersion and decomposition of phenol.

This paper reports the synthesis of magnetic CoFe 2 O 4 −reduced graphene oxide (rGO) hybrids and the catalytic performance in heterogeneous activation of peroxymonosulfate (PMS) for decomposition of phenol. The surface morphologies and structures of the CoFe 2 O 4 −rGO hybrids were investigated by field emission scanning electron microscopy (SEM), energydispersive X-ray spectrometer (EDS), transmission electron microscopies(TEM), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption−desorption isotherm, and thermogravimetric analysis (TGA). Through an in situ chemical deposition and reduction, CoFe 2 O 4 −rGO hybrids with CoFe 2 O 4 nanoparticles of 23.8 nm were produced. Catalytic testing showed CoFe 2 O 4 −rGO hybrids exhibited much better catalytic activity than CoFe 2 O 4 , which suggests rGO plays an important role in CoFe 2 O 4 −rGO hybrids for the decomposition of phenol. Moreover, the hybrid catalyst presents good magnetism and could be separated from solution by a magnet.

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Facile chemical approaches for the controllable synthesis of CuSe, CuInSe2 nanowire, and CuInSe2/CuInS2 core/shell nanocable bundles were developed. Hexagonal CuSe nanowire bundles with lengths up to hundreds of micrometers, consisting of many aligned nanowires with a diameter of about 10-15 nm, were prepared by reacting cubic Cu(2-x)Se nanowire bundles with a sodium citrate solution at room temperature. The CuSe nanowire bundles were then used as self-sacrificial templates for making bundles of tetragonal chalcopyrite CuInSe2 nanowires by reacting with InCl3 via a solvothermal process. Furthermore, bundles of CuInSe2/CuInS2 core/shell nanocables were obtained by adding sulfur to the reaction system, and the shell thickness of the polycrystalline CuInS2 in the nanocables increased with increasing S/Se molar ratios. It was found that the small radius of copper ions allows their fast outward diffusion from the interior to the surface of nanowires to react with sulfur atoms/anions and indium ions to form a CuInS2 shell. Enhanced optical absorption in the vis-NIR region of CuInSe2/CuInS2 core/shell nanocable bundles is demonstrated, which is considered beneficial for applications in optoelectronic devices and solar energy conversion.