Dongfeng Sun

Facile solvothermal synthesis of BiOCl–TiO2 heterostructures with enhanced photocatalytic activity

BiOCl–TiO2 heterostructures with different Bi to Ti molar ratios were synthesized via a facile one-pot solvothermal process. The as-synthesized BiOCl–TiO2 heterostructures included TiO2 nanoparticles deposited on the surface of BiOCl nanoplates. X-ray photoelectron spectroscopy results revealed the TiO2 of BiOCl–TiO2 heterostructures doped with Bi3+, reduced the band gap energy of the sample. The photocatalytic efficiencies were evaluated by degradation of methylene blue dye under simulated sunlight illumination. Results indicated that the BiOCl–TiO2 heterostructures with Bi : Ti = 1 : 3 exhibited the highest photocatalytic efficiency, which is 73.5 times and 8.5 times higher than that of single phase BiOCl and TiO2, respectively. In addition, the radical species involved in the degradation process have been investigated by scavenger experiments. Finally, a new mechanism for the photocatalytic action of the BiOCl–TiO2 heterostructures was put forward.

Synthesis and infrared shielding properties of molybdenum-containing ammonium tungsten bronzes

A series of molybdenum-containing ammonium tungsten bronzes was synthesized by a solvothermal process at 200 °C for 72 h using ethylene glycol, acetic acid, ammonium tungstate and ammonium molybdate as starting materials. All the diffraction peaks of XRD for the samples synthesized with starting Mo/W (mol) = 0–0.2 could be rough indexed as a hexagonal ammonium tungsten bronze with the formula of (NH4)0.33WO3, which was accompanied by a shift of the main peaks after the introduction of molybdenum and a split peak for starting Mo/W (mol) = 0.1. The nitrogen content, based on both the thermogravimetry and X-ray photoelectron spectroscopy, rose with the increase of molybdenum content. Optical properties were evaluated using Fourier transform infrared spectroscopy, which proved that the molybdenum-containing ammonium tungsten bronzes could shield infrared rays better than the sample without molybdenum. The shield efficiency was related to the content of molybdenum. The optimum starting Mo/W (mol) to obtain high infrared shielding properties was 0.1. This sample consisted of uniform rods of ca. 50 nm in diameter emerging from the agglomerates.

Facile synthesis of superparamagnetic Fe3O4 nanoparticles just using ferric citrate and water

ABSTRACT Fe3O4 nanoparticles were synthesized by a facile one-pot hydrothermal process just using ferric citrate and water without any additional reagent and post-treatment. The temperature of hydrothermal reaction had important influence on the crystallinity and magnetic property of Fe3O4 samples. Fe3O4 sample synthesized at 200 °C for 24 h showed a narrow size distribution (4 to 8 nm in diameter), and exhibited apparent superparamagnetism with saturated magnetization of 55.1 emu/g. The narrow size distribution and superparamagnetism were the interesting features of these Fe3O4 nanoparticles.