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Graphical abstract Abstract In this paper, the photocatalytic degradation of organic pollutants was investigated using Ag/ZnS nanoparticles at different noble metal loadings. The photocatalysts were prepared at room temperature by two different methods: photodeposition and chemical reduction. The obtained samples were characterized by Specific surface area measurement, X-ray photoelectron spectroscopy, X-ray Powder diffraction, ultraviolet–visible diffuse reflectance and Raman spectroscopy. The X-ray photoelectron spectroscopy spectra showed that Ag is present on ZnS surface as intermediate state between nanostructured Ag0 and Ag 2 O. Moreover, the addition of silver caused a significant change of the absorption spectrum of bare ZnS, resulting in higher absorbance in the visible region, due to the Ag surface plasmon band. Methylene blue (MB) was used to evaluate the photocatalytic activity of the prepared samples. The best photocatalytic activity was observed using the sample at 0.1 wt% Ag loading prepared by chemical reduction method. In particular, the almost complete MB degradation was achieved using UV-LEDs as light sources and 6 g L−1 of catalyst dosage. Finally, the optimized photocatalyst was also effective in the degradation of phenol in aqueous solution under UV irradiation. [ABSTRACT FROM AUTHOR]

Chemical, structural, morphological and micro-/macro-electrical properties of undoped and nitrogen-(N-)doped diamond films are determined by X-ray photoelectron spectroscopy, Raman and photoluminescence spectroscopies, field emission scanning electron microscopy, atomic force microscopy, scanning capacitance microscopy (SCM) and two points technique for I–V characteristics, respectively. The characterization results are very useful to examine and understand the relationship among these properties. The effect of the nitrogen incorporation in diamond films is investigated through the evolution of the chemical, structural, morphological and topographical features and of the electrical behavior. The distribution of the electrical current is first assessed at millimeter scale on the surface of diamond films and then at micrometer scale on small regions in order to establish the sites where the carriers preferentially move. Specifically, the SCM images indicate a non-uniform distribution of carriers on the morphological structures mainly located along the grain boundaries. A good agreement is found by comparing the electrical currents at the micro- and macro-scale. This work aims to highlight phenomena such as photo- and thermionic emission from N-doped diamond useful for microelectronic engineering. [ABSTRACT FROM AUTHOR]

Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications and wound healing. This work aims to investigate the surface chemical composition and biological properties of silver nanoparticle-modified flax substrates. Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution, by means of a large-scale apparatus. The silver-coated materials were characterized through X-ray Photoelectron Spectroscopy (XPS), to assess the surface elemental composition of the coatings, and the chemical speciation of both the substrate and the antibacterial nanophases. A detailed investigation of XPS high resolution regions outlined that silver is mainly present on nanophases' surface as Ag 2 O. Scanning electron microscopy and energy dispersive X-ray spectroscopy were also carried out, in order to visualize the distribution of silver particles on the fibers. The materials were also characterized from a biological point of view in terms of antibacterial capability and cytotoxicity. Agar diffusion tests and bacterial enumeration tests were performed on Gram positive and Gram negative bacteria, namely Staphylococcus aureus and Escherichia coli . In vitro cytotoxicity tests were performed through the extract method on murine fibroblasts in order to verify if the presence of the silver coating affected the cellular viability and proliferation. Durability of the coating was also assessed, thus confirming the successful scaling up of the process, which will be therefore available for large-scale production. [ABSTRACT FROM AUTHOR]