Search

A visible light-driven AgBr/Ag 2 CO 3 nanosheets composite has been fabricated via a in-situ ultrasonic anion-exchange method at room temperature, using Na 2 CO 3 and cetyltrimethyl ammonium bromide (CTAB) as carbonate anion and bromide anion resources, respectively. The X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) analysis demonstrated that the obtained products were consisted of AgBr nanoparticles and Ag 2 CO 3 nanosheets, in addition the AgBr nanoparticles were well distributed on the surface of sheet-like Ag 2 CO 3 to form AgBr/Ag 2 CO 3 heterostructure. Evaluation of the prepared AgBr/Ag 2 CO 3 hybrids photocatalytic activity by degradation of Rhodamine B (RhB) or Methyl orange (MO) under visible light irradiation (λ>420 nm) indicated they have efficient and higher photocatalytic activities compared to the pure AgBr and Ag 2 CO 3 samples, which could be related to the matched band potential band potential between AgBr and Ag 2 CO 3 . Besides, a possible photocatalytic mechanism of the hybrids was also proposed.

In this letter, graphene oxide (GO) was prepared by a kind of modified Hummers' method, which via ultrasonic treatment could be dispersed in water to obtain a homogeneous and stable brownish yellow flocculent solution. AgBr/Ag/Ag2O/GO nanocomposite catalyst was produced by adding hexadecyltrimethyl ammonium bromide (CTAB) and silver nitrate solution into the above formed GO solution under ultrasonic treatment. The structures, morphologies, and light absorption properties of AgBr/Ag/Ag2O/GO composite catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and ultraviolet and visible diffuse reflectance spectroscopy (UV-DRS). Preliminary results showed that the composite catalyst has a better catalytic degradation effect on organic dyes like rhodamine B (RhB) and methyl orange (MO) in polluted water under simulated solar light irradiation in contrast to the single GO and AgBr.

Hierarchically structured hollow microspheres composed of copper sulfide (CuS) nanoplatelets have been successfully fabricated via a one-pot and green sonochemical process for the first time, using copper acetate and thiourea aqueous solution as precursors without surfactant or template. Large-scaled hollow architectures with outer diameters in the range of 1–1.2 μm are assembled by pure hexagonal single crystalline CuS nanoplatelets, being of about 20 nm in thickness with stacking faults in the crystal lattice. The UV-Vis diffuse reflectance spectra (DRS) analysis suggests that the band gap energy of the as-obtained CuS sample was estimated to be 1.27 eV, showing a significant red-shift compared with the bulk value. Hollow CuS structures possess the high surface area and double pore size distributions as measured from the N2 adsorption isotherms. Moreover, the possible growth mechanism for CuS hollow spheres is proposed on the basis of the temporal evolution controlled experiments. More importantly, this hierarchically structured CuS catalyst show highly efficient Fenton-like catalytic activity in degrading highly concentrated dye-containing solution (50 mg·mL−1) with the help of hydrogen peroxide (H2O2), suggesting a promising application in wastewater purification.

AgBr/Ag3PO4 composite quasi-microcubes were fabricated by a simple ultrasonic synthesis method, in which hexadecyltrimethylammonium bromide was used as Br resource and surfactant. The structures and morphologies of the as-obtained product were initially characterised by X-ray diffraction, field emission scanning electron microscopy and energy dispersive X-ray analysis spectroscopy. The ultraviolet–visible diffuse reflectance spectrum of the as-obtained products demonstrated that this hybrid structure exhibits an enhanced absorption ability in the visible region. Furthermore, the composite products exhibit much higher photocatalytic performance and stability on degradation of rhodamine B dye under the stimulated sunlight irradiation compared with pure AgBr and Ag3PO4.

This paper presents the results of a study in which nanosized titanium dioxide (TiO{sub 2}) crystal particles were coated onto the surface of palygorskite fibrous clay which had been modified by silver ions using titanium tetrachloride as a precursor. Coated TiO{sub 2} particles with the anatase structure were formed after calcining at 400 deg. C for 2 h in air. Various analytical techniques were used to characterize the surface properties of titanium dioxide particles on the palygorskite. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses showed that TiO{sub 2} particles were supported on the surface of the palygorskite clays and their size was in the range of 3-6 nm. The titanium oxide coatings were found to be very active for the photocatalytic decomposition of methylene blue.

Titanium dioxide coated on copper modified palygorskite clay nanocomposite (Cu 2+ -PG/TiO 2 ) prepared by hydrolysis method was used as photocatalyst in the degradation reaction of methylene blue. The surface characteristics of copper modified palygorskite coated with TiO 2 particles was confirmed by the X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), Brunauer–Emmett–Teller (BET) surface area analysis and X-ray photoelectron spectrometer (XPS). The incorporation of Cu 2+ did not change the structure of the palygorskite. The size of anatase particles was relatively small ( 2+ -PG/TiO 2 as high as 198.6 m 2 /g were measured for catalysts containing 0.6 wt.% copper and 25 wt.% titanium dioxide. The photocatalytic activity of those nanocomposite photocatalysts was much higher than that of the pure titanium dioxides.

Porous magnetite (Fe 3 O 4 ) microspheres can be direct acquired by hydrothermal reaction of Fe-citrate complex (Fe (NH 4 ) 2 H (C 6 H 5 O 7 ) 2 ) in neutral solution. Results show that the obtained Fe 3 O 4 particles are nearly spherical in shape and about 2 μm to 3 μm in mean diameter. Every magnetite microsphere is made of many ultrafine Fe 3 O 4 nanoparticles and porous in structure. The as-prepared porous magnetite microspheres have higher surface area (~ 83 m 2 /g) and excellent magnetic properties (M s = 81 emu/g, H c = 145 Oe) at room temperature.

Step-wise self-assembled flower-like δ-Bi2O3 microspheres from nanoparticles to nanosheets to microspheres were fabricated via a simple hydrothermal process, using glycine and Bi (NO3)3·5H2O as starting materials without other additives. The crystal structures and morphologies of the as-obtained samples were characterised by X-ray powder diffraction, field emission scanning electron microscope and transmission electron microscopy. The UV–vis diffuse reflectance spectrum of the sample showed the product has an intense absorption in UV light regions and an estimated bandgap 3.55 eV. Moreover, under UV-light irradiation the sample exhibited high photocatalytic behaviour for the degradation of rhodamine B dye and excellent stability, which possibly has a board application in wastewater disposal fields.