Authors:Shi Xu, Sheng Li, Yun Wei, Li Zhang and Fei Xu
Titanium dioxide (TiO2), polythiophene and polythiophene/TiO2 were prepared by sol–gel and solid-state reaction methods. Water-free iron(III) chloride (FeCl3) was used as an oxidant. The phase composition, morphology and the spectral properties of the products were characterized by XRD, TEM, UV–Vis and FT-IR techniques. The photocatalytic activity of the products was evaluated by the degradation of methyl orange under sunlight irradiation. TEM results showed that the polythiophene/TiO2 composite particles were well dispersed, rod-like shaped with 20 × 80 nm dimensions. UV–Vis analysis indicated that the absorption edge of polythiophene/TiO2 was 605 nm. Compared with the unmodified TiO2 and bare polythiophene, polythiophene/TiO2 exhibited largely enhanced activity for the photocatalytic degradation of methyl orange under sunlight irradiation. A degradation efficiency of methyl orange of 85.6% could be obtained within 120 min. The sensitization mechanism of polythiophene for the TiO2 photocatalyst is discussed briefly.
Authors:Ying Xu, Man Xue, Jinjin Li, Liujie Zhang and Yuanchen Cui
A cellulose xanthate supported palladium(0) complex was synthesized using a simple method and characterized by XPS, TG/DTA
etc. The complex has good thermal stability from room temperature to 250 °C and it was found to be an efficient catalyst for
the Heck reaction of acrylic acid or styrene with aryl iodide at low temperature under atmospheric pressure, and the substituted
trans-cinnamic acid or 1, 2-stilbene was obtained with high yield at 90 °C. The reaction duration is about 8 h. The cellulose xanthate
supported palladium(0) complex could be separated from the reaction mixture easily and reused for several cycles. The yield
of the product was up to 55.3% when the catalyst was run for 10 times. The active center in the complex is Pd metal.
Authors:Bing Xue, Yongxin Li, Shujun Wang, Hongyan Liu and Chongfu Xu
Selective synthesis of ethylbenzene by vapor phase alkylation of benzene with diethyl carbonate was carried out over MCM-22
modified by MgO. Characterization results show that the number of Brønsted acid sites on MCM-22 decreased significantly after
MgO modification, which resulted in a decrease in activity. The selectivity for ethylbenzene was improved greatly over MCM-22
modified by MgO, which can be attributed to the effective suppression of subsequent alkylation of ethylbenzene by the reduction
in Brønsted acid sites.
Authors:Bing Xue, Kai Jia, Jie Xu, Na Liu, Ping Liu, Chongfu Xu and Yongxin Li
An efficient and novel method to prepare KNO3/NaY solid base catalysts was developed. High selectivity for phenetole along with high conversion of phenol was obtained in the vapor phase O-alkylation of phenol with diethyl carbonate over KNO3 modified NaY zeolite. Experimental results showed that a large number of basic sites on KNO3/NaY were generated mainly during catalytic evaluation, which was responsible for the outstanding catalytic performance. Furthermore, the excess KNO3 loadings might lead to the blockage of the pores in the NaY zeolite and decrease the catalytic activity.
Authors:Guangsong Sun, Hui Xu, Huaming Li, Huoming Shu, Chengtang Liu and Qi Zhang
Gd2O3/Ag3VO4 photocatalysts are synthesized through the impregnation method and characterized by powder X-ray diffraction (XRD), X-ray
photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectra (DRS). It is shown
that Gd3+ is dispersed on the surface of Ag3VO4 in the form of Gd2O3. The DRS analysis indicates that the ability of visible-light absorption of Gd2O3/Ag3VO4 catalysts is enhanced greatly. The photocatalytic activities of the samples are evaluated by degradation of Rhodamine B dye
under UV and visible-light irradiation, respectively. The experimental results show that the role of Gd2O3 content has a significant impact on the photocatalytic activities of the samples. The mechanism of enhanced photocatalytic
activity after the Gd introduction is discussed.