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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]

Nanocrystals of undoped and nickel-doped zinc oxide (ZnNiO, where x = 0.00-0.05) were synthesized by the coprecipitation method. Crystalline size, morphology, and optical absorption of prepared samples were determined by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and UV-visible spectrometer. XRD and SEM studies revealed that Ni-doped ZnO crystallized in hexagonal wurtzite structure. Doping of ZnO with Ni was intended to enhance the surface defects of ZnO. The incorporation of Ni in place of Zn provoked an increase in the size of nanocrystals as compared to undoped ZnO. Crystalline size of nanocrystals varied from 10 to 40 nm as the calcination temperature increased. Enhancement in the optical absorption of Ni-doped ZnO indicated that it can be used as an efficient photocatalyst under visible light irradiation. Optical absorption measurements indicated a red shift in the absorption band edge upon Ni doping. The band gap value of prepared undoped and Ni-doped ZnO nanoparticles decreased as annealing temperature was increased up to 800 °C. [ABSTRACT FROM AUTHOR]