Jingxia Yang

Enhanced Sunlight Photocatalytic Performance of Hafnium Doped ZnO Nanoparticles for Methylene Blue Degradation

A series of Hf-doped ZnO nanocatalysts were synthesized by sol–gel method with a doping content up to 6 mol%. The structure, morphologies, and optical properties of the synthesized catalysts were characterized by XRD, TEM, FTIR and UV–Vis absorption spectrometer. The photocatalytic activity was evaluated by the Methylene Blue degradation in aqueous solution under sun light irradiation. Irradiation time and doping content had important effects on the photocatalytic activity of Hf-doped ZnO. Hafnium content had an optimum value of 2 mol% for achieving high photocatalytic activity. The experiments demonstrated that MB was effectively degraded up to 85% within 120 minutes. It was confirmed that the presence of Hafnium in ZnO catalysts could enhance the photocatalytic oxidation.

Solvothermal Preparation of Carbon-Enhanced TiO2/Graphene Composite and Its Visible Light Photocatalytic Properties

Carbon-enhanced TiO2/graphene composite photocatalyst was prepared by two-step method. First, anatase TiO2 nanocrystals with amorphous carbon layer (C-TiO2 nanocrystals) were obtained in acetone solvothermal condition. Then, graphene was coated by reduction from graphite oxide and simultaneously combined with the C-TiO2 nanocrystals in a one pot solvothemal reaction. The structure, morphology, optical and photocatalytic properties of the samples were investigated. This carbon-enhanced TiO2/graphene shows high visible light photosensitivity and favorable photocatalytic activity toward methyl orange.

Sol-gel Synthesis and Photoluminescence Characterization of Ba2SiO4:Eu2+ Green Phosphors for White-LED Application

In this paper, Ba2SiO4:Eu2+ green phosphor was synthesized by sol-gel method. TGA-DTA, XRD, SEM and PL spectra were used to characterize the as-prepared phosphors. The phosphors are composed of nanoparticles with 60 nm grain size and exhibit green light with a broad peak around 500 nm. The relationship between crystal growth, morphology and luminescent properties was studied. The structure and luminescence properties of phosphors synthesized in different conditions were also discussed.

Tuning the Band Gap of Stable and Dispersible Graphene Aqueous Solution via Hydrothermal Reduction Method

A well dispersed graphene aqueous solution was achieved by hydrothermal reduction method, in which graphene oxide (GO) was reduced by employing an effective reagent of hydrazine hydrate (N2H4•H2O). The reduction degree of reduced graphene oxide (RGO) was preciously regulated via different reduction time. The obtained products were confirmed by X-ray diffraction, scanning and transmission electron microscopy, Fourier-transform infrared spectroscopy. The energy band gap of reduced graphene with different reaction time was characterized by ultraviolet-visible spectroscopy. The results showed that hydrothermal reduction method is a simple and efficient approach to synthesizing the dispersed graphene nanosheets aqueous solution, which is stable for several months without obvious precipitates or stratification in basic solvent. The energy band gap of different degree of reduction RGO can be tuned tremendously via controlling the reduction time.