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Cocrystallization Method of Porous Nanostructures Synthesis Uladzimir Novikau1,2, Sviatlana Filipovich1, Anna Daletskaya1, Irina Sharapava1, and Ihar Razanau2 1 SSPA “Scientific and Practical Material Research Centre of NAS of Belarus”, 19 P. Brovki Street, 220072, Minsk, Belarus. 2 “Advanced Research and Technologies” LLC, 1 Sovhoznaya Street, Leskovka, Minsk, Belarus. ABSTRACT The paper describes a novel electrochemical method of metal nanowire synthesis via coherent cocrystallization of metal with metal salt. Using the method described, iron, copper, and tin nanowires as well as lead nanowalls in the matrix of ferrous chloride FeCl2 salt were synthesized. Influence of electrolyte composition and electrolysis regime on the deposit structure is revealed. Morphology, chemical composition, and structure of the NW@salt nanocomposite is studied and discussed. INTRODUCTION Nanostructured materials are characterized by high surface-to-volume ratio leading to a significant increase of their chemical activity. Therefore, nanostructure synthesis methods are closely related to their stabilization methods. To exclude interaction and stabilize nanosize objects, they are isolated from each other in bulk and porous matrices. The template synthesis of nanowires [1, 2] allows for reproducibility of geometrical and physical properties of the objects. However, each type of matrix allows forming only a certain size and morphology of nanostructures as the size of the nanoparticles cannot excel the size of the nanoreactor. On the other hand, the template-free methods of synthesis [3, 4] neither allow for formation of uniformly shaped and sized nanowires nor provide metal nanowires chemical stabilization. The present study is dedicated to an electrochemical method of metal nanowires formation. The method is based on cathodic cocrystallization of a salt and a metal during the electrolysis. The study covers patterns of the growth process and the major factors affecting the hierarchically organized structure formation. EXPERIMENT Nanocomposites of metal nanowires in inorganic salt matrices were synthesized electrochemically in a galvanostatic regime. The synthesis was carried out under the constant current density of 10-100 mA/cm2. Graphite rods were used as cathodes, iron or copper rods were used as anodes. Salts containing metal ions of Sn+2, Pb+2, Cu+2, and Fe+3 were dissolved in dimethylformamide (DMF) for electrolyte preparation. DMF is an aprotic solvent and thus, it prevents side cathodic reaction of hydrogen reduction characteristic of aqueous electrolytes. To bind the water that was introduced to the electrolytes with the metal salt hydrates, anhydrous

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CaCl2 was added as well. The salts used for electrolyte preparation are characterized by high solubility in DMF. Hence, the order of component dissolution does not affect the process. The electrolyte was cooled down to 10 °C as the salt matrix of the deposited nanocomposites was easily dissolved by the electrolyte under higher temperature. The duration of the electrolysis was