Qingsheng Wu

A novel method for crystal control: synthesis and design of strontium carbonate with different morphologies by supported liquid membrane

A biomimetic supported liquid membrane (SLM) system was employed to control the morphology of strontium carbonate. Some interesting morphologies, including rods, shuttles and spheres, can be readily generated by using citric acid, nitrilotriacetic acid and ethylenediaminetetraacetic acid as cooperative modifiers in the mineralization process, under the conditions of pH 10, 0.01% of crystal modifier and ambient temperature. Seeking the cooperative balance of the SLM, the modifier agent and its concentration is the key factor in this system. In addition, this method was successfully applied to the morphology control of other alkaline earth metal carbonates, indicating its general applicability in materials preparation.

Biomimetic synthesis of BaSO4 nanotubes using eggshell membrane as template

BaSO 4 nanotubes were biomimetically synthesized by the combined assembly of eggshell membrane and C 12 H 25 SH. The products were tubular structure with the external diameter of 90–140 nm and the length of 1.5–2.5 μm. The formation mechanism was also investigated. It provided a novel method for the fabrication of inorganic oxysalt nanotubes.

Facile synthesis of hierarchical porous carbon via the liquidoid carbonization method for supercapacitors

A facile method is used to synthesize honey derived hierarchical porous carbon materials for supercapacitor application. The specific surface area and pore size distribution can be modified with different mass ratios of KOH at 800 °C under a N2 atmosphere. The activated materials synthesized in a 3u2006:u20061 ratio of KOH to char possess the maximum specific capacitance of 271 F g−1 at 1 A g−1 in a 6 M KOH electrolyte, and retain up to 212 F g−1 even at 10 A g−1 current density. In addition, these materials also show excellent capacity retention of 98% at 10 A g−1 after 3000 cycles. The excellent electrochemical performance is attributed to high specific surface area and appropriate pore size distribution.

Biomimetic synthesis of Ag2CrO4 quasi-nanorods and nanowires by emulsion liquid membranes

Semiconductor Ag2CrO4 quasi-nanorods and nanowires have been successfully prepared through novel emulsion–liquid membrane technology. The membrane phase in this system consists of Span-80 as the surfactant, N7301 as the carrier (or free carrier), and kerosene as the solvent. The internal aqueous phase is 0.1 M AgNO3 and the external aqueous phase is 0.1 M K2Cr2O7. Under the conditions of Roi = 2.0, Rew = 0.5, [Span-80] = 6% (v/v), and room temperature, Ag2CrO4 quasi-nanorods with diameters of 180–300 nm and lengths of up to 2300 nm, or nanowires with diameters of 15–25 nm and lengths of up to 1000 nm, were obtained in the presence or absence of 5% (v/v) N7301, respectively. X-Ray diffraction and transmission electron microscopy were used to characterize the structure and morphology of the Ag2CrO4 quasi-nanorods and nanowires. In addition, the photoluminescence spectrum showed strong emissions.

Solvothermal synthesis of well-disperse ZnS nanorods with efficient photocatalytic properties

Well-disperse short-range-ordered ZnS nanorods with efficient photocatalytic property for photodegradation of Rhodamin B have been successfully synthesized through a solvothermal method. Solvent used can be recovered and reused, which makes the route environment-friendly. Dodecylamine was found effective in organizing nanorods to ordered monolayer. Characterization showed that these nanorods were uniform with the diameter of about 3 nm and length of nearly 30 nm. And it is expected that these monodisperse ZnS nanorods have potential applications in electroluminescence materials.

A novel additive‐free oxides–hydrothermal approach for monazite‐type LaPO4 nanomaterials with controllable morphologies

A facile oxides–hydrothermal (O–HT) method is demonstrated to prepare high-purity monazite-type LaPO4 nanomaterials. In this approach, La2O3 and P2O5 powder are first directly used as precursors under additive-free hydrothermal conditions. The as-prepared samples are characterized with X-ray diffraction, Fourier transform IR spectroscopy, thermogravimetry, scanning electron microscopy, transmission electron microscopy (high-resolution TEM, energy dispersive spectroscopy) and selected-area electron diffraction. The typical sample obtained at 433u2005K in 24u2005h comprises uniform single-crystal nanofibres with a diameter of ∼15–28u2005nm and an aspect ratio of 30–50. The influences of treatment time, synthesis temperature and P/La molar ratio are investigated. The phase transition from hexagonal hydrate to monoclinic anhydrous lanthanum phosphate and the growth process of nanofibres are revealed by the experimental results. The formation mechanism of the monoclinic LaPO4 is discussed. The result indicates that the P/La ratio does not influence the composition and crystal phase but changes the morphology of the product in the O–HT system.

Assembly of nano-superstructural aragonite CaCO3 by living bio-membrane

Biomimetic living templates, mung bean sprouts (MBS), were employed to control the crystallisation of calcium carbonate. Metastable aragonite superstructure can be readily generated in normal conditions. Some interesting morphologies including elaborate piny dendritic, flowerlike and rods were also prepared using citric acid, nitrilotriacetic acid and ethylenediaminetetraacetic acid as cooperation modifiers in the mineralisation process, under the conditions of 0.01% of crystal modifier and ambient temperature. These morphologies were assembled by some elaborate substructures, similar to nanowire and featherlike crystals. The products were characterised by SEM, XRD and FTIR, respectively. The results indicated that the formation of aragonite polymorph of calcium carbonate was favoured in this system. A probable mechanism was proposed.

Synthesis and characterization of ZnS nanotubes with crossed-channels

ZnS nanotubes with crossed-channels have been synthesized successfully using a hydrothermal method. A novel hydrothermal reaction of simultaneous solvent-oxidation-hydrolysis has been developed using Zn powder, H2O and NH2CSNH2 as reagents. TEM images show that each branch of the channels is about 400-500 nm long. The inner diameter is 55 nm, the outer diameter is 70 nm, and the interlayer spacing is about 7 nm. XRD data show that the product is well-crystallized in the cubic Sphalerite phase. The peak appears at 293 nm in the UV-Vis absorption spectrum, which is about 50 nm blue shifted from the bulk counterpart. The photoluminescence spectrum of ZnS nanotubes shows that the emission peak occurs at 409 nm when excited at 365 nm.

FeOOH nanorod arrays aligned on eggplant derived super long carbon tube networks as negative electrodes for supercapacitors

A beautiful and unique super long carbon tube network structure was synthesized via a freeze-drying technique and then carbonization of natural eggplant in a nitrogen atmosphere. Subsequently, nanorod-like FeOOH arrays were evenly grown on the surface of the carbon material via an easy and efficient hydrothermal process without any toxic chemicals. The composites grown for 5 h exhibited excellent performance, including a specific capacitance of 396 F g−1 within a potential window of −1.08 to 0 V at a current density of 0.5 A g−1 (2 times that of the pure eggplant derived carbon) and a good cycling stability (83% over 500 cycles at a current density of 10 A g−1). It is speculated that the synergistic effect of the super long hollow carbon tube network and the nanorod-like FeOOH arrays contributes to the fast electron transport and the battery-type capacitance behavior, respectively, thus enhancing the electrochemical performance. The above results indicate that the prepared nanocomposites are a potential negative electrode for supercapacitors.

Synthesis of brush-like CdS nanorod arrays through a novel hydrothermal reaction of simultaneous solvent-oxidation-hydrolysis

Brush-like CdS arrays composed of well-arranged nanorods have been successfully synthesized for the first time through a novel chemical reaction under the low-temperature hydrothermal condition. The reaction can be described as the solvent-oxidation-hydrolysis reaction among Cd, H2O and thiourea. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL). TEM results showed that these nanorods were about 20u2009nm wide with lengths varying from 1.25u2009µm to 3.5u2009µm. XRD pattern indicated that as-obtained CdS was hexagonal phase with good crystallinity. PL spectrum showed the products had novel optical property from the bulk counterpart. The formation mechanism was also explored.