Photocatalytic Degradation of Methyl Orange using MoS2 nanoparticles as catalyst

MoS2 is a semiconductor transition metal dichalcogenide material (TMD) which has exciting optoelectronic properties. Due to its band gap (BG) energy lying in the visible range it shows good photocatalytic behavior. In this report, we have synthesized MoS2 nanoparticles (NPs) and its morphology is characterized using XRD and SEM. EDX is performed to analyze the composition of the as-synthesized material. Multiple BG energy in the visible light range is observed from the analysis of UV-Visible spectroscopy. We have investigated the photocatalytic property by the degradation of Methyl Orange (MO) using MoS2 nanoparticles as catalyst. It is observed that the as-synthesized MoS2 NPs degrade MO very efficiently with 98% degradation using 1mg in 1ml 10μM dye solution in 2hr

Investigating photocatalytic activity of titania coated fresh water diatom frustules by the degradation of polluting dye

Silica frustules of diatoms contain nanoscale pores arranged in periodic order. In this report we have synthesized TiO2 nanoparticles coated diatom frustules followed by annealing at 500ºC. The as synthesized DT500 catalyst is characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM) and EDX. UV-visible spectroscopy is performed to analyze the band gap (BG) energy of the material which is found to lie in the visible light range. The photocatalytic properties of the catalysts are investigated via typical polluting dye as a model organic compound under visible light irradiation. The as synthesized DT500 catalyst contains anatase phase of titania exhibited more light absorption in the visible region and found to have higher photocatalytic efficiency due to morphology of frustules and TiO2 coating

Synthesis of Ag nanoparticles using diatom cells for ammonia sensing

Growth of silver nanoparticles through photo induced bioreduction mechanism on the surface of diatom cells, which is a kind of photosensitive fresh water organism containing hydrated amorphous silica structure, has been found to be a cost-effective, rapid, non-toxic, eco-friendly, photo-induced bottom-up process. This material shows broad absorbance in the visible light spectra. Light sensitive fucoxanthin pigment of diatoms that contain hydroxyl (−OH) groups, play a vital role in the formation of silver cluster on the surface of diatom cells and its growth process. Involvement of the compounds and proteins of the diatoms which are responsible for reduction of metal ions and stabilization of the grown nanoparticles on diatom cells, are confirmed by FTIR analysis. Investigations are done to see if the synthesized samples acted as sensing material in the fabrication of a room temperature sensor of dissolved ammonia. With increase in ammonia concentration the visible light absorption peaks tend to higher intensity with blue shift due to the formation of [Ag(NH3)2]+ complexes causing repulsion between the Ag nanoparticles and consequently lead to the formation of smaller Ag nanoparticles. The intensity of absorption of the as-synthesized material is linearly correlated with the concentration of dissolved ammonia as observed from 0 to 100ppm. The use of naturally occurring diatoms for Ag nanoparticles synthesis has the benefits of amenability for large-scale easy production. Also the experimental findings indicate that the as-synthesized material can act as fast and reliable sensing material. Keywords: Diatoms, Fucoxanthin, Silver nanoparticles, Ammonia senso