Mechanochemical and sonochemical syntheses of new nanocomposites

Abstract

For the first time the possibility of the complex nanodispersed compound formation at mechanochemical and sonochemical treatment of the initial compounds mixture was shown. Mechochemical treatment of the mixture of molybdenum oxide and bismuth nitrate permits to obtain of bismuth molybdate in form of nanoparticles, in the same time the treatment of mixture of titanium oxide and calcium hydroxide leads to formation of calcium titanate in form of nanoprisms. It was shown that mechanochemical treatment of the mixture of titanium oxide and tin oxide leads to formation of titanium oxide amorphous layer on tin oxide surface. The mechanism of nanodispersed zinc molybdate formation at sonochemical treatment of initial oxides was established. It was shown that nanocomposites synthesized by these methods demonstrate the higher catalytic activity in organic compounds neutralization processes in water solutions at visible light irradiation and in the process of bioethanol selective oxidation to acetaldehyde and hydrogen in comparison with known analogous catalysts synthesized by traditional methods.

Gold leaf tesserae: tracing the origins of gold using synchrotron-based techniques

“…4 the gold leaf tesserae with gilded objects (gold leaf < 1 μm) and gold leaf (> 1 μm) and foil (< c.30 μm) of very different chronology, although produced around the Mediterranean basin. They are Egyptian, Middle Kingdom to Roman Period [75,[101][102][103]; Hellenistic and Roman, from Greece [104], Italy [105], and Thracia [106]; and mediaeval [21,107,108]. The gold leaf < 1 μm thick (tesserae and gilding) forms the same chemical pattern in the ternary diagram, and the majority contain more than 97 wt% Au.…”