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Abstract: Cu doped ZnS nanoparticles (Zn1−x Cu x S; where x=0.00, 0.03, 0.05 and 0.10) were synthesized by a chemical precipitation method. The synthesized products were characterized by X-ray diffraction, scanning electron microscope, high resolution transmission electron microscope, ultraviolet-visible and photoluminescence spectrometer. The X-ray diffraction and high resolution transmission electron microscope studies show that the size of crystallites is in the range of 2–10nm. XRD study revealed that the samples are composed of cubic phase without doping and at 3mol% Cu doping concentration while at the doping of 5mol% and 10mol% Cu, phase transition from cubic blende to hexagonal phase occurs in ZnS. Photocatalytic activities of ZnS and 3, 5 and 10mol% Cu doped ZnS were evaluated by decolorization of methylene blue in aqueous solution under ultraviolet and visible light irradiation. It was found that the Cu doped ZnS bleaches methylene blue much faster than the undoped ZnS upon its exposure to the visible light as compared to the ultraviolet light. The optimal Cu/Zn ratio was observed to be 3mol% for photocatalytic applications. [Copyright &y& Elsevier]

Highlights: [•] Fe doped ZnS nanoparticles were synthesized by a chemical precipitation method. [•] ZnS powders calcined at 100°C are in cubic phase and the size of crystallites is in the range of 2–5nm. [•] Photocatalytic activity of Fe doped ZnS significantly higher under visible light as compared to UV light. [•] Optimal concentration of Fe doped ZnS was observed to be 3mol% for photocatalytic applications. [ABSTRACT FROM AUTHOR]

Abstract: Fe doped CdS nanoparticles (Cd1−x Fe x S; where x =0.00, 0.03, 0.05 and 0.10) were synthesized by a chemical precipitation method. The synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Raman and UV–vis spectrometer. The XRD and TEM measurements show that the size of crystallites is in the range of 2–10nm. With increased the Fe doping concentration, the position of the Raman bands shifted towards higher wavenumbers and their intensities decreased drastically. Optical measurements indicated that the absorption band edge shifted towards longer wavelength upon Fe doping. Direct allowed band gap of undoped and Fe doped CdS nanoparticles measured by UV–vis spectrometer were 2.3 and 2.2eV at 100°C, respectively. Photocatalytic activities of CdS and Fe doped CdS were evaluated by irradiating the solution of methylene blue (MB) and sample under visible light. It was found that Fe doped CdS bleaches MB much faster than undoped CdS upon its exposure to the visible light. The optimum Fe/Cd ratio was observed to be 3mol% for photocatalytic applications. In contrast, little degradation was observed for the pure CdS powder. [Copyright &y& Elsevier]

Abstract: Mn-doped TiO2 nanoparticles (Ti1− x Mn x O2; where x =0.00–0.10) were synthesized by sol–gel method. The synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and UV–Vis spectrometer. The SEM and TEM micrographs revealed the agglomerated spherical-like morphology and measurements show that the size of crystallites is in the range of 10–20nm. Optical measurements indicated a red shift in the absorption band edge after Mn doping. Direct allowed band gap of undoped and Mn-doped TiO2 nanoparticles measured by UV–Vis spectrometer were 3.00 and 2.95eV at 300°C, respectively. Photocatalytic activities of TiO2 and Mn doped TiO2 were evaluated by irradiating the sample solution of methylene blue (MB) dye under ultraviolet and visible light exposure. It was found that Mn-doped TiO2 bleaches MB much faster than undoped TiO2 upon its exposure to the visible light as comparison to ultraviolet light. The experiment demonstrated that the photodegradation efficiency of Mn-doped TiO2 was significantly higher than that of undoped TiO2 upon its exposure to visible light. [Copyright &y& Elsevier]