Xiao-Feng Cao

BiOBr hierarchical microspheres: Microwave-assisted solvothermal synthesis, strong adsorption and excellent photocatalytic properties.

Two kinds of BiOBr nanosheets-assembled microspheres were successfully prepared via a facile, rapid and reliable microwave-assisted solvothermal route, employing Bi(NO(3))(3)·5H(2)O and cetyltrimethylammonium bromide (CTAB) as starting reagents in the absence or presence of oleic acid. The phase and morphology of the products were characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Experiments indicated that the formation of these building blocks of microspheres could be ascribed to the self-assembly of nanoparticles according to mesocrystal growth mode. Interestingly, both samples exhibited not only strong adsorption abilities, but also excellent photocatalytic activities for methyl orange (MO), rhodamine B (RhB) and phenol. The resulting BiOBr hierarchical microspheres are very promising adsorbents and photocatalysts for the treatment of organic pollutants.

Persimmon-like (BiO)2CO3 microstructures: hydrothermal preparation, photocatalytic properties and their conversion into Bi2S3

We report here the preparation of self-assembled persimmon-like (BiO)2CO3 microstructures via a simple hydrothermal process. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), selected area electron diffraction (SAED) and high resolution transmission electron microscopy (HRTEM) were employed to characterize the phases and morphologies of the products. The reactants could greatly influence the phases and morphologies of the final products. The growth process of the persimmon-like (BiO)2CO3 microstructures has been investigated. The persimmon-like (BiO)2CO3 could be utilized as a sacrificial template to synthesize sphere-like Bi2S3 microstructures by a chemical transformation process. The as-prepared (BiO)2CO3 was able to efficiently degrade Rhodamine B (RhB) and eosin sodium salt under simulated solar irradiation.

Microwave-assisted solution-phase preparation of flower-like Bi2WO6 and its visible-light-driven photocatalytic properties

We report here the preparation of flower-like Bi2WO6via a simple, rapid, microwave-assisted solution-phase process. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HRTEM) were employed to characterize the phase and morphologies of the products. The time-dependent experiments showed an Ostwald ripening mechanism in the crystal growth process. The as-prepared Bi2WO6 was able to efficiently degrade Rhodamine B (RhB) under visible light irradiation. Calcination was found to decrease the photocatalytic performance of flower-like Bi2WO6.

Pancake-like Fe2(MoO4)3 microstructures: microwave-assisted hydrothermal synthesis, magnetic and photocatalytic properties

A fast and economical route based on microwave-assisted hydrothermal reaction has been developed to synthesize pancake-like Fe2(MoO4)3 microstructures. The phase and morphology of the products have been characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Several factors, including the amount of nitric acid, reaction time, temperature and iron source, play crucial roles in the formation of the Fe2(MoO4)3 multilayer stacked structures. Detailed studies indicate that the oriented attachment and layer-by-layer self-assembly of nanosheets is responsible for the formation of these structures. The magnetic and photocatalytic properties of the product have also been investigated.

Microwave-assisted solution-phase preparation and growth mechanism of FeMoO4 hierarchical hollow spheres

In the present paper, we report successful synthesis of FeMoO4 hierarchical hollow spheres with 1.0 µm in diameter via a simple, rapid and reliable microwave-assisted solution-phase approach. The phases and morphologies of the products have been characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Some factors influencing the morphology of the final product have been investigated. These experiments indicate that the self-assembly of FeMoO4 nanoparticles at the water/gas interface is responsible for the formation of a hierarchical hollow structure.

Microwave-assisted solvothermal synthesis and growth mechanism of WO3·(H2O)0.33 hierarchical microstructures

WO3·(H2O)0.33 hierarchical microstructures such as micro-nutlets, micro-flowers, and micro-discs have been successfully prepared via a facile microwave-assisted solvothermal route employing Na2WO4·2H2O and hydrochloric acid as precursors and disodium ethylenediaminetetraacetic (Na2H2EDTA) as a structure-directing agent. The products have been characterized by X-ray powder diffraction (XRD), energy dispersive X-ray analysis (EDS) scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The influences of reaction time, temperature, the volume ratio of water and glycerol, and the amount of Na2H2EDTA and hydrochloric acid on the morphologies have been studied in detail. A possible growth mechanism was proposed.

Microwave-assisted preparation and photocatalytic properties of Zn2GeO4 nanorod bundles

Well-aligned Zn2GeO4 nanorod bundles were successfully prepared via a facile microwave-assisted solution-phase approach. The phase and morphology of the product were characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM). Such rhombohedral phase Zn2GeO4 bundle-like microstructures were found to be constructed by abundant single crystalline nanorods of 40–70 nm in diameter and ∼800 nm in length. Some influencing factors such as the reaction time, temperature, the volume of ethylenediamine and PEG-400 were revealed to play crucial roles in the formation of Zn2GeO4 nanobundles. A possible growth mechanism was proposed based on the experimental results. Moreover, the photocatalytic properties of as-prepared Zn2GeO4 nanobundles were studied, and they exhibited excellent photocatalytic activities for degradation of methyl orange and rhodamine B under UV light irradiation.

Fast preparation and growth mechanism of erythrocyte-like Cd2Ge2O6 superstructures via a microwave-hydrothermal process

Monodisperse erythrocyte-like Cd2Ge2O6 superstructures have been successfully prepared via a facile and fast microwave-assisted solution-phase approach, employing Cd(Ac)2·2H2O and GeO2 as the reactants in the presence of hydrazine monohydrate. The phase and morphology of the product were characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Such monoclinic phase Cd2Ge2O6 microstructures were found to be constructed by abundant single crystalline nanoneedles. Some influencing factors such as the reaction time, reaction temperature, the volume of hydrazine monohydrate and the cadmium source were revealed to play crucial roles in the formation of the Cd2Ge2O6 architecture. A possible growth mechanism was proposed based on the experimental results.

Preparation and Characterization of Flowerlike Y2(OH)5NO3·1.5H2O and Y2O3 and Their Efficient Removal of Cr(VI) from Aqueous Solution

A simple sonochemical procedure was developed to synthesize the flowerlike yttria precursor Y2(OH)5NO3·1.5H2O. Y2O3 with the same morphology was readily obtained by calcination of the precursor. The microstructures and morphologies of the products were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and field-emission scanning electron microscopy (FESEM). The as-obtained Y2O3 and its precursor were found to be effective sorbents for the removal of Cr(VI) ions in water treatment, as a result of the novel hierarchical structures and high specific surface areas of these two materials.