Papers by Author: Xin Ping Lin

Abstract: A series of layered-structure Bi-based oxychlorides such as BiOCl, Bi3O4Cl, Na0.5Bi1.5O2Cl, Bi4NbO8Cl and MBiO2Cl (M = Ca, Sr, Ba, Cd, Pb) used as efficient photocatalysts. Among them, Bi3O4Cl (Eg = 2.79 eV), Na0.5Bi1.5O2Cl (Eg = 3.03 eV), Bi4NbO8Cl (Eg = 2.38 eV) and PbBiO2Cl (Eg = 2.45 eV) are visible-light-responsive. The powders synthesized by solid state reactions were characterized by X-ray diffraction (XRD) and UV-Vis diffuse reflection spectrum. Their photocatalytic activities were evaluated by the degradation of methyl orange. The results generally show that the UV-induced photocatalytic performances of the novel oxychloride catalysts are better than or comparable to that of anatase TiO2. The high photocatalytic performance of Bi-based oxychlorides is mainly ascribed to the presence of strong internal static electric fields between layers.

Abstract: Eu-doped CaS phosphors were prepared from sulfurization of CaCO3 in H2S gas without flux. The doping of Eu activator was conducted in two different modes: synchronous doping during sulfurization of CaCO3 and subsequent doping by vacuumly calcinning pure CaS and Eu2O3. Comparison of the as-prepared samples indicated that subsequent doping led to larger optimum Eu concentration and lower red emission intensity than synchronous doping. The different luminescence properties are ascribed to the different activator distributions in CaS host induced by different doping modes, and the uniform distribution resulted from synchronous doping is beneficial to the luminescence of the phosphor.

Abstract: ZnS:Cu,Cl phosphors were synthesized by high temperature (1200 °C) solid state reaction, mechanical milling (rotation speed = 0, 75, 150, 250 and 350 r / min) and the final annealing at 750 °C for 1 h in different atmospheres (hydrogen sulfide, sealed evacuated silica tubes and Ar). The as-prepared phosphors were characterized by X-ray powder diffraction and photoluminescence spectra. It was found that mechanical milling led to width increases of diffraction peaks. Both the mechanical milling and atmosphere play important roles in the photoluminescence performance of the phosphors. Some phosphors prepared by the three-step method possess higher photoluminescence performances than the normal one-step method. Particularly, the luminescence intensity of the phosphor milled at the rotation speed of 75 r / min and then treated in Ar atmosphere is about one time higher than that prepared by the normal one-step process.