Annealing Temperature Effect on Structural and Luminescence Spectroscopy of Y2SiO5:Ce3+ Nanomaterial Synthesized by Sol–Gel Method

Ce3+ - doped Y2SiO5 nanophosphors were successfully produced by Sol-Gel process. To study the influence of the temperature on the structure and the luminescence of Y2SiO5:Ce3+, we annealed the xerogels at the temperatures 800, 900, 950, 1000, 1050 and 1250 °C. The X-ray diffraction technique (XRD), field emission scanning electron microscopy (FEG-SEM), Fourier transform infrared spectroscopy (FTIR) and steady photoluminescence were used to characterize the samples. The crystallite size keeps the same value in the temperature range 950-1050 °C. The room temperature steady photoluminescence emission and excitation of Ce3+ in X1-Y2SiO5:Ce3+ nanomaterial with increasing temperature were measured and investigated. At the crystallization temperature of 1250 °C, we have a new structure X2- Y2SiO5:Ce3+ with grain sizes larger than the X1-Y2SiO5:Ce3+ and also intense violet-blue emission

Efficient synthesis of zinc-containing mesoporous silicas by microwave irradiation method and their high activities in acetylation of 1,2-dimethoxybenzene with acetic anhydride

A series of acid zinc-containing mesoporous materials have been synthesized by microwave irradiation method with different Si/Zn ratios (Si/Zn = 100, 65, 15) and characterized by several spectroscopic techniques such as: N2 physical adsorption, ICP, XRD, TEM, FT-IR and a temperature-programmed-desorption (TPD) of pyridine. The liquid phase of acetylation of 1,2-dimethoxybenzene with acetic anhydride has been investigated over this series of catalysts. In fact, the catalyst Zn-JLU-15 (15) showed bigger performance in the acid-catalyzed acetylation of 1,2-dimethoxybenzene employing acetic anhydride as an acylating agent. Furthermore, the kinetics of the acetylation of 1,2-dimethoxybenzene over these catalysts have also been investigated

New way for iron introduction in LDH matrix used as catalysts for Friedel–Crafts reactions

The alkylation of toluene, reaction employing benzyl chloride as the alkylating agent over basic hydrotalcite materials: Fe–Mg–Al-LDH prepared by different synthesis methods, including the method of co-precipitation, impregnation and a new method called the method of intercalation by anion exchange in the lamellar space of the host structure LDH. Our prepared solids were characterized by chemical analysis, XRD analysis, BET method and thermogravimetric analysis (TGA) and tested in the alkylation of toluene by benzyl chloride reaction. Fe–Mg–Al-LDH clay without or with calcination (at 773 K) has been investigated. The catalyst derived from the hydrotalcite by its calcination at 773 K shows high catalytic activity for the alkylation of toluene and other aromatic compounds. The catalytically active species present in the catalyst in its most active form are the oxides of iron on the catalyst surface