Enhancement in the photocatalytic activity of Ag loaded N-doped TiO2 nanocomposite under sunlight

A N-doped titania–silver nanocomposites have been prepared by simple microwave assisted and impregnation–reduction method for the first time. As synthesized nanocomposites with different Ag contents were characterized for their phase purity, morphology, particle size, optical properties and elemental composition. It is found that N-doped TiO₂ silver nanocomposites are pure in anatase phase with an average crystallite size of 10 nm. The catalyst was tested for dye degradation and photodegradation efficiency was found to be 99.6 and 88.7 % within 90 min under UV and sunlight respectively. A 40 % enhancement in the photodegradation efficiency was achieved by Ag loading in comparison with the N-TiO₂ under sunlight. The fluorescence quenching of Ag loaded N-TiO₂ indicates decrease in rate of electron–hole pair recombination that enhances photocatalytic performance. The effects of photocatalytic operational parameters such as method of surface modification, catalyst loading and irradiation sources on the photodegradation of methyl orange were also investigated.     

Room temperature synthesis of CdS nanoflakes for photocatalytic properties

Herein, we report, preparation of cadmium sulphide (CdS) nanoflakes at room temperature by simple arrested precipitation method. The synthesized CdS nanoflakes were characterized by various techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform-infrared spectroscopy, and UV–Visible spectrophotometer. Nanoflakes of CdS were found to be a mixed-phases composed of cubic and hexagonal with average crystallite size of 20 nm. Surface morphology of CdS seems to be nanoflakes. The absorption spectrum was slightly shifted to blue region as compared to the bulk, this indicates that synthesized material is smaller in size. The band gap energy was found to be 2.48 eV. The photocatalytic results reveals that CdS nanoflakes exhibits excellent photocatalytic performance for methyl orange (20 ppm) degradation, under sunlight and UV within 120 min (83 and 95 % respectively).