Synthese und funktionelle Anwendungen hoch-photokatalytischer TiO2-basierter Oberflächen: Al/TiO2- und Au/TiO2-Hybridstrukturen

The interest in using heterogeneous photocatalysis as an alternative for environmental clean-up is continuously increasing as the water resources diminish enormously and the air pollution threatens human health seriously. TiO2 is one of the mostly preferred material for heterogeneous photocatalysis due to its inertness, non-toxicity, high photocatalytic activity, recyclability and safety towards humans and nature. This dissertation covers the development of TiO2 based highly photocatalytic thin films and their functional applications.Das Interesse heterogene Photokatalyse als Alternative für die Beseitigung von Umweltbelastungen zu nutzen, steigt kontinuierlich an, da die Wasserressourcen schrumpfen und die Luftverschmutzung eine ernsthafte Bedrohung für die menschliche Gesundheit darstellt. TiO2 ist eines der bevorzugtesten Materialien für die heterogene Photokatalyse, dank seiner Inertheit, Ungiftigkeit, hohen photokatalytischen Aktivität, Wiederverwertbarkeit und Sicherheit gegenüber Mensch und Natur. Diese Dissertation umfasst die Entwicklung von auf TiO2 basierenden, photokatalytisch hochaktiven Dünnschichten und ihre funktionellen Anwendungen

Cross Sectional Study and Risk Factors Analysis of Francisella tularensis in Soil Samples in Punjab Province of Pakistan

Tularemia is an endemic zoonotic disease in many parts of the world including Asia. A cross-sectional study was conducted to determine genome-based prevalence of Francisella tularensis (Ft) in soil, assess an association between its occurrence in soil and likely predictors i.e., macro and micro-nutrients and several categorical variables, and determine seroconversion in small and large ruminants. The study included a total of 2,280 soil samples representing 456 villages in eight districts of the Punjab Province of Pakistan followed by an analysis of serum antibodies in 707 ruminants. The genome of Ft was detected in 3.25% (n = 74, 95% CI: 2.60–4.06) of soil samples. Soluble salts (OR: 1.276, 95% CI: 1.043–1.562, p = 0.015), Ni (OR: 2.910, 95%CI: 0.795–10.644, p = 0.106), Mn (OR:0.733, 95% CI:0.565–0.951, p = 0.019), Zn (OR: 4.922, 95% CI:0.929–26.064, p = 0.061) and nutrients clustered together as PC-1 (OR: 4.76, 95% CI: 2.37–9.54, p = 0.000) and PC-3 (OR: 0.357, 95% CI: 0.640, p = 0.001) were found to have a positive association for the presence of Ft in soil. The odds of occurrence of Ft DNA in soil were higher at locations close to a water source, including canals, streams or drains, [χ2 = 6.7, OR = 1.19, 95% CI:1.05–3.09, p = 0.004] as well as places where animals were present [χ2 = 4.09, OR = 2.06, 95% CI: 1.05–4.05, p = 0.02]. The seroconversion was detected in 6.22% (n = 44, 95% CI: 4.67–8.25) of domestic animals. An occurrence of Ft over a wide geographical region indicates its expansion to enzootic range, and demonstrates the need for further investigation among potential disease reservoirs and at-risk populations, such as farmers and veterinarians

Ultra-fast degradation of methylene blue by Au/ZnO-CeO2 nano-hybrid catalyst

Au/ZnO-CeO2 hybrid structure was prepared by in-situ synthesis of 15-20 nm CeO2 particles in aqueous environment, in which ZnO particles ( 400-500 nm) were dispersed, using surfactant assisted precipitation method. Au was loaded on prepared structures through the reduction of AuCl3 by ascorbic acid. TEM analysis and Raman spectroscopy showed that synthesized hybrid structure is composed of both hexagonal ZnO and cubic CeO2 phases. While methylene blue test solution was degraded totally within 8 min in the presence of Au/ZnO-CeO2 hybrid catalysis, use of Au/ZnO and Au/CeO2 led to a significantly low degradation rate (about 22% and 11%, respectively). As proven by XPS analysis the incorporation of ZnO to CeO2 seem to trigger the formation of Ce+3/Ce+4 dynamic equilibria and this enhances the catalytic efficiency enormously. (C) 2017 Elsevier B.V. All rights reserved

Growth of Highly c-Axis Oriented AlScN Films on Commercial Substrates

In this work, we present a method for growing highly c-axis oriented aluminum scandium nitride (AlScN) thin films on (100) silicon (Si), silicon dioxide (SiO2) and epitaxial polysilicon (poly-Si) substrates using a substrate independent approach. The presented method offers great advantages in applications such as piezoelectric thin-film-based surface acoustic wave devices where a metallic seed layer cannot be used. The approach relies on a thin AlN layer to establish a wurtzite nucleation layer for the growth of w-AlScN films. Both AlScN thin film and seed layer AlN are prepared by DC reactive magnetron sputtering process where a Sc concentration of 27% is used throughout this study. The crystal quality of (0002) orientation of Al0.73Sc0.27N films on all three substrates is significantly improved by introducing a 20 nm AlN seed layer. Although AlN has a smaller capacitance than AlScN, limiting the charge stored on the electrode plates, the combined piezoelectric coefficient d33,f with 500 nm AlScN is only slightly reduced by about 4.5% in the presence of the seed layer

Role of UV Plasmonics in the Photocatalytic Performance of TiO₂ Decorated with Aluminum Nanoparticles

We present a facile method, combining sputtering and gas aggregation techniques, to prepare a photocatalytic TiO₂ thin film decorated with stable aluminum plasmonic nanoparticles (Al NPs) to reveal the localized surface plasmon resonance (LSPR) effect on TiO₂ photocatalysis under UV irradiation. We demonstrate for the first time the negative and positive influences of LSPR on UV photocatalysis by irradiating Al NPs/TiO₂ hybrid structures at two different UV wavelengths: both at and above the plasmonic absorption of Al NPs. These findings open the door to design low-cost Al/TiO₂ photocatalytic hybrid surfaces that function in a broad spectral range from deep-ultraviolet to visible wavelengths