Keynote Lecture
Sonochemistry of Molten Metals

When a sonochemical horn is placed in molten metals covered by silicon oil a precipitate is formed in a few minutes despite the temperature being above the metal`s melting point. This method fits metals whose mp is lower than 430 ⁰C, namely, Hg, Ga, In, Pb, Sn, Cd, Bi, and Zn. In the case of Ga whose melting point is 29.8 ⁰C water can be used as the overlayering the molten Ga. The reaction that is carried with water can be conducted at 60 ⁰C (30 degrees above the melting point) and still a solid precipitates to the bottom of the test tube. The reason is a film that is formed on the metal surface preventing a liquid to be formed. For Ga we have encapsulated organic molecules in the metal and even imprented chirality in Ga. For the seven metals an organic liquid is used above the metal the coated layer was a film of carbon. The supernatant is composed of small C-Dots and more interesting nanoparticles of Metal@C-dot were also found in the supernatant. The doped C-Dots were characterized by all the conventional Materials Science techniques such as XRD, HRTEM, HRSEM, ICP and more. We were able to vary the doping level by changing the amount of the metal used. C-Dots are well-known for their fluorescence properties, and the emission spectrum of the Metal@C-Dots is different from that of pristine C-Dots. A few examples of the application of the metal dopes C-Dots will be demonstrated. For example Ga@C-dots showed very good biocidal properties against Pseudomonas aeruginosa. The metal@C-Dots were used in catalysis as well as in building electrodes for rechargeable Li batteries.