Hong Chao Ma

Constructing TiO2/Gr with Rapid Electrons Transfer for Efficiency Photocatalysis

TiO2/Gr powders were fabricated by hydrothermal method. Their micro-structure was characterized by transmission electron microscopy (TEM). The results revealed TiO2 particles anchored on the Gr sheets. DRS analysis indicated there was an obvious red shift of the absorption edge of TiO2/Gr compared to that of TiO2. The experiment of photocatalytic degradation of Rhodamine B (RhB) showed that the degradation rate with TiO2/Gr was 2.40 times as much as that with TiO2. The enhanced photocatalytic performance was firstly attribSubscript textuted to the rapid transfer of the photogenerated electrons from TiO2 to Gr, which could increase the charge carrier separation, limit their recombination, and enhance the photocatalytic efficiency. Furthermore, the extended light absorption range may also contribute to the enhanced photocatalytic performance.

Preparation of Polyaniline Supported TiO2 Photocatalyst and its Photocatalytic Property

A polyaniline supported titanium dioxide photocatalyst was prepared by an impregnation-hydrothermal process and characterized by powder X-ray diffraction, transmission electron microscopy and UV-visible spectroscopy. It was found that the TiO2 nanoparticles were well dispersed on the surface of the polyaniline and the photocatalyst has a stronger absorption compared with that of pure TiO2 over the whole of the visible spectrum. The photocatalyst exhibited higher photocatalytic activity than pure TiO2 for the photodegradation of solutions of the anthraquinone dye, reactive brilliant blue KN-R, under visible light irradiation.

Hydrothermal Synthesis of ZnO/Zn Composites with Enhanced Photocatalytic Performance

ZnO/Zn composites photocatalysts were prepared by hydrothermal method using Zn powder as raw material, and the morphology, structure, and photocatalytic performance of composites were investigated. The results showed that the ZnO nanoparticles were produced at the surface of Zn metal powder during hydrothermal process. The thickness of ZnO outer layer (internal metal-semiconductor interfaces) can be controlled by varying hydrothermal treatment time. The resulting ZnO/Zn composites exhibit significantly higher photocatalytic activity than that of pure ZnO for degradation of anthraquinone dye (reactive brilliant blue KN-R) aqueous solution under ultraviolet light irradiation. The enhancement of photocatalytic performance of ZnO/Zn composites can be attributed to the formation of internal metal-semiconductor interfaces. The designed fabrication procedure is simple, feasible, and universal for a series of oxide/metal with controlled microstructure and improved performances.

Preparation of Polyaniline–ZnO Photocatalyst and its Photocatalytic Property

ZnO nanoparticles were modified by polyaniline (PANI) using ‘in situ’ chemical oxidative polymerization method. The morphology, structure, and light absorption properties of PANI-ZnO composites were examined by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis spectra. UV–vis spectra reveal that PANI-ZnO composites showed stronger absorption than neat ZnO under the whole range of visible light. New characteristic peaks were found in PANI-ZnO composites according to the X-ray diffraction patterns after hybridization of PANI and ZnO, which indicating that there was a strong interaction between PANI and ZnO nanoparticles. The resulting PANI-ZnO composites exhibit significantly higher photocatalytic activity than that of neat ZnO for degradation of anthraquinone dye (reactive brilliant blue KN-R) aqueous solution under visible light irradiation (λ > 420 nm).

Effects of Mg2SiO4 Addition on the Microstructure and Dielectric Properties of MgTiO3-CaTiO3 Ceramics

The Mg2SiO4-MgTiO3-CaTiO3 composite dielectric ceramics with different Mg2SiO4 addition amounts were prepared by solid state reaction method. The effects of Mg2SiO4 addition amounts on the microstructure and dielectric properties as well as sintering temperature of xMg2SiO4-(0.95-x)MgTiO3-0.05CaTiO3 (abbreviated as xMSTC, 0.25≦x≦0.75) composite ceramics were investigated. The results indicated that the sintering temperature of MgTiO3-CaTiO3 based ceramics with Mg2SiO4 addition could be lowered effectively to 1320~1340°C, and the dielectric constant decreased and dielectric loss increased gradually with the increase of Mg2SiO4 content. The 0.45MSTC ceramics containing 45 wt% Mg2SiO4 and sintered at 1340°C showed desirable dielectric properties with dielectric constant εr=13.3，dielectric loss tanδ=4.5×10-4 and temperature coefficient of relative permittivity τε =10 ppm/°C.

Preparation of TiO2/AC and Investigation of its Photocatalytic Activity

TiO2/AC composite was prepared by sol-gel method. The effect of annealed temperature and loading (or doping) ratio of AC on photocatalytic performances of TiO2/AC composite was explored. The optimum preparation conditions were 400 °C (annealed temperatur) and 2% (loading (or doping) ratio of AC). The experimental results of MB removal showed that the photocatalytic ability of TiO2/AC composite prepared under optimum conditions was higher than that of TiO2, which could be attributed to strong adsorption capacity, efficient photoproduced electron-hole separation, and higher light response.

Degradation of Reactive Brilliant Blue KN-R by Zero-Valent Iron/Activated Carbon Combined with Ultrasound

The treatment of Reactive Brilliant Blue KN-R in wastewater was conducted by using the zero-valent iron/activated carbon (Fe0/AC) combined with ultrasound (US). Although ultrasound alone had a little effect on the KN-R degradation and Fe0/AC had some disadvantages when it acted on the KN-R, the efficiency of the degradation was dramatically enhanced which used the combination of Fe0/AC /U.S. that also could eliminate the shortcomings. The decolorization percentage was nearly up to 100% and the COD removal rate has approached to 87.38%.

Oxidative Degradation of Azo Dye Reactive Red 2BF by Potassium Ferrate

The oxidative degradation of azo dye Reactive Red 2BF in aqueous solution by using potassium ferrate (Ⅵ) was studied. The initial concentration of wastewater 100 mg/L, pH 4.0, reaction time 20 min, and the dosage of potassium ferrate was 0.9 g/L. Under the optimal conditions, the decolorizing rate of Reactive Red 2BF and the COD removal rate were 99.9% and 73.3%.

Response of Urban Roadside Greening Plant Exposed to Automobile Exhaust Pollution

The changes of chlorophyll, malondialdehyde(MDA) and the catalase(CAT) activity in mature leaves of a common urban roadside greening plant------- Buxus sinica were studied. The results show that under automobile exhaust polluted environment, the contents of chlorophyll a, chlorophyll b and total chlorophyll decreased while the content of MDA and the activity of CAT increased. These changes have correlation with the automobile exhaust pollution.

Microwave Assisted Hydrothermal Synthesis and Characterization of N, S Co-Doped ZnO Photocatalyst

The N, S codoped ZnO was synthesized by microwave assisted hydrothermal method. The N, S codoping narrowed the band gap of ZnO (formed impurity states in the band gap), hence shift light response to range of visible light. Furthermore, the doped ZnO exhibits significantly higher photocatalytic activity than that of pure ZnO for degradation of reactive brilliant blue KN-R aqueous solution under simulative solar irradiation.