Effective method of obtaining of the bactericidal bandage materials by impregnation of cotton fabric by aqueous solutions of silver and copper salts followed by a certain regime of heat treatment is developed. The study of obtained materials by methods of optical spectroscopy, electron microscopy, and X-ray phase analysis showed the formation of crystalline silver nanoparticles (NPs) and bimetallic Ag/Cu composites with the corresponding surface plasmon resonance (SPR) bands in the absorption spectra. High antimicrobial and antimycotic properties of tissues with low concentrations of Ag and Ag/Cu nanoparticles (Ag/Cu NPs) (in the range 0.06–0.25 weight percent (wt%) for Ag and 0.015–0.13 wt% for Ag/Cu) is confirmed in experiments with a wide range of multidrug-resistant bacteria and fungi: Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, Klebsiella pneumoniae, Candida albicans yeasts, and micromycetes. Textile materials with Ag NPs demonstrate high antibacterial activity, while fabrics doped with bimetallic composite Ag/Cu have pronounced antimycotic properties. Bactericidal and antifungal properties of the obtained materials do not change after a washing. Production of such materials is extremely fast, convenient, and cost-effective.
Nanoscale composite materials based on titanium dioxide, sulphur, and carbons were obtained. The samples were characterized using X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller and Barret-Joiner-Halenda methods, electron paramagnetic resonance spectroscopy, and ultraviolet-visible and infrared spectroscopy. X-ray powder diffraction revealed the phase of anatase in all composites and appearance of rutile phase for samples with high sulphur content. It was established that composites consist of nanoparticles ca. 6-10 nm. Analysis of nitrogen adsorption-desorption isotherms for the synthesized samples showed the presence of a hysteresis loop which is the evidence for mesoporous structure of the powders. Absorption spectra of nanocomposites showed a bathochromic shift compared with the absorption band of pure TiO 2 . It was found that modification of titanium dioxide with sulphur and carbons leads to bandgap narrowing of composites. Nanocomposite samples showed higher photocatalytic activity in the destruction of safranin T under ultraviolet and visible irradiation compared to pure titanium dioxide. It can be connected with the participation of additives in the inhibition of electron-hole recombination, prolongation of charges lifetime, increasing of efficiency of interfacial charge separation, and formation of doping electronic states.
Produced by templated sol-gel method mesoporous nanosized titania powders modified with 3d-metal ions have been characterized by XPS and TPR methods. Metal species formed on the titania surface were investigated. The TPR analysis showed that reduction behaviors of the M n+ /TiO 2 were strongly affected by the synthesis method, preparation conditions and interactions between the dopant metal and TiO 2 matrix. It was found that Ti-O-M-bonds formation during sol-gel synthesis with applying nonionic triblock copolymer Pluronic P123 as organic template and calcination at 550 °C promoted high-dispersion states of doped 5 % metals. The XPS and TPR showing dopants exist as divalent and trivalent ions for M n+ /TiO 2 , where M=Co, Ni, Mn, and as monovalent and divalent ions in the case of Cu/TiO 2 .
Mesoporous nanosized titania films modified with Co2+, Ni2+, Mn3+, and Cu2+ ions have been produced by templated sol-gel method and characterized by optical spectroscopy, X-ray diffraction (XRD), and Brunauer, Emmett, and Teller (BET) surface area measurement. Band gap energy and the position of flat band potentials were estimated by photoelectrochemical measurements. The films doped with transition metals possessed higher photocurrent quantum yield, as well as photo- and electrochemical activity compared to undoped samples. Mn+/TiO2 (M–Co, Ni, Mn, Cu) electrodes with low dopant content demonstrate high efficiency in electrocatalytic reduction of dissolved oxygen. Polarization curves of TiO2, TiO2/Ni2+, TiO2/Co2+/3+, and TiO2/Mn3+ electrodes contain only one current wave (oxygen reduction current). It means that reaction proceeds without the formation of an intermediate product H2O2.
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