Yinfang Cui

Lotus-root-like NiO nanosheets and flower-like NiO microspheres: synthesis and magnetic properties

The synthesis of lotus-root-like NiO nanosheets and flower-like NiO microspheres was realized through a simple hydrothermal method and subsequent calcination. The diameter of the lotus-root-like NiO nanosheets is about 400 nm and the pore size is about 5∼20 nm. The diameter of the flower-like NiO microspheres is about 2.5 μm, and are composed of staggered lotus-root-like nanosheets. During the synthetic procedure, aqueous ammonia was used as an alkaline complexing reagent, and PVP was used as the template. Interestingly, when the pH value of the precursor solution increased from 8.30 to 10.80, the NiO nanosheets gradually assembled into microspheres, indicating that aqueous ammonia plays a key role in controlling the final morphology. Based on the experimental observation and analysis, a possible mechanism is proposed to understand the formation of the NiO nanostructured materials. In addition, the resultant NiO nanostructures present anomalous magnetic properties and display a spin-glass state at low temperature.

Synthesis and photocatalytic properties of Cu 2 O/BiOCl semiconductor films

Cu2O/BiOCl composite films were synthesized by a simple two-step-method: sol-gel dip-coating technique and magnetron sputtering. At first, the BiOCl thin film was prepared on indium tin oxide (ITO) substrate via a simple sol-gel dip-coating technique. Then the Cu2O thin film was fabricated on the surface of the BiOCl thin film by magnetron sputtering. Their photocatalytic activities were evaluated by photocatalytic degradation of Rhodamine B (RhB) under UV and visible light irradiation, respectively. It was found that the photocatalytic activity of the Cu2O/BiOCl composite films was higher than single BiOCl thin film and single Cu2O thin film. The photocatalytic efficiency of the as-synthesized films seems to strongly depend, that is mainly due to both of the Cu2O works as a sensitizer absorbing visible light and the Cu2O/BiOCl hetero-junction promoting the separation rate of photo-generated electron-hole pairs. The mechanism has been discussed on the interparticle charge transfer between two semiconductors while they have the suitable relative band position.