Browsing by Subject "Photo catalytic degradation"

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Electrospun BiOI nano/microtectonic plate-like structure synthesis and UV-light assisted photodegradation of ARS dye
(Royal Society of Chemistry, 2014) Babu, V. J.; Bhavatharini, R. S. R.; Ramakrishna, S.
BiOI electrospun nanofibers were prepared by using PAN as a supporting polymer. Subsequent annealing at 500 °C for 5 h, with a ramp rate of about 5 °C min-1 in air, breaks the nanofibers down to tectonic plate-like nano/microstructures. The surface physical and chemical structural changes were then further characterized by FE-SEM, TEM, XRD and XPS. The results reveal that the morphology and crystallite size of BiOI vary strongly depending on the precursor concentration used in the synthesis method. These nanostructures were later employed for photocatalytic degradation of a synthetic textile dye, Alizarin Red S (ARS). The photocatalytic efficiencies were found to be about 93.34% after 100 min of UV-light (340 nm) illumination. Photocatalytic activity (PCA) performance depends on morphology and band alignment. All the compositions follow first order pseudo-kinetics, which was found to be 0.1197 min-1 for a doping concentration of 3%. The enhancement in photodegradation could be possibly by photocatalysis and a photosensitization phenomenon. This has been explained based on the band edge position. © the Partner Organisations 2014.
Open Access
Fast and quick degradation properties of doped and capped ZnO nanoparticles under UV-Visible light radiations
(Elsevier Ltd, 2016) Mittal, M.; Sharma, M.; Pandey, O. P.
Undoped and Manganese (Mn) doped zinc oxide (ZnO) (Zn1- xMnxO, x=0.005, 0.01, 0.015 and 0.02) nanoparticles (NPs) capped with (1.0%) Thioglycerol (TG) has been successfully synthesized by co-precipitation method. Optical and morphological studies have been done for photophysical and structural analysis of synthesized materials. The photocatalytic activity of undoped and Mn doped ZnO NPs were investigated by degradation of crystal violet (CV) dye under UV-Visible light radiations. It has been found that Mn (1.0%) doping concentration is optimal for photophysical and photocatalytic properties. When the pH of as synthesized optimum doped ZnO NPs varied from natural pH i.e. from 6.7 to 8.0 and 10.0, the degradation of CV dye increases from 92% to 95% and 98% in 180min respectively. Further on increasing the pH of optimum doped synthesized NPs to 12.0, almost 100% degradation has been achieved in 150min. Optimum doped photocatalyst synthesized at pH-12.0 has also effectively degraded the CV dye solution in acidic and basic medium thus showed its utility in various industries. However, it has been found that 100% of CV dye quickly degraded in 30min when only 1.0% of hydrogen peroxide (H2O2) was introduced along with optimized NPs synthesized at pH-12. Kinetic studies show that the degradation of CV dye follows pseudo first and second-order kinetic law. Further an industrial anionic polyazo Sirius red F3B (SRF3B) dye has been degraded to 100% with optimized NPs synthesized at pH-12.0 in 15min only.
Open Access
A versatile bio-inspired material platform for catalytic applications: Micron-sized "buckyball-shaped" TiO2 structures
(Royal Society of Chemistry, 2015) Erdogan, D. A.; Solouki, T.; Ozensoy, E.
A simple sol-gel synthesis method is presented for the production of micron-sized buckyball-like TiO2 architectures using naturally occurring Lycopodium clavatum (LC) spores as biotemplates. We demonstrate that by simply altering the calcination temperature and titanium(iv) isopropoxide : ethanol volume ratio, the crystal structure and surface composition of the buckyball-like TiO2 overlayer can be readily fine-tuned. After the removal of the biological scaffold, the unique surface morphology and pore structure of the LC biotemplate can be successfully transferred to the inorganic TiO2 overlayer. We also utilize photocatalytic degradation of Rhodamine B dye samples to demonstrate the photocatalytic functionality of these micron-sized buckyball-like TiO2 architectures. Moreover, we show that the photocatalytic activity of TiO2 overlayers can be modified in a controlled manner by varying the relative surface coverages of anatase and rutile domains. These results open a potential gateway for the synthesis of a variety of bio-inspired materials with unique surface properties and shapes comprised of reducible metal oxides, metal sulfides, mixed-metal oxides, and/or perovskites.