Copper oxide nanowires represent a popular topic in recent research due to their potential use in gas sensors, batteries, supercapacitors etc. One of their advantages is facile synthesis, as they can be synthesized merely by heating metallic copper in the air. Moreover, their parameters, such as length and diameter, can be easily tailored by adjusting the conditions at which they are synthesized. Once obtained, nanowires can be further processed to enhance their properties. Common processing includes a partial or complete transformation of grown nanowires to another phase via cation or anion exchange. There are many existing methods for achieving such transformations, which are mostly solution-based. On the other hand, great unused potential lies in methods that exploit plasmas to achieve phase transformations in nanomaterials.

Even though there are a lot of reports on the synthesis of CuO nanowires, there are still a lot of knowledge gaps when it comes to their production and ion exchange reactions. In both cases, the challenges are associated with fundamental science behind processes during nanowire growth and phase transformations, as mechanisms behind NW growth and ion exchange reactions are not completely understood. In our present research, we tackle challenges connected to the thermal growth of CuO nanowires as well as the fundamental science behind phase transformations in them. In order to study mechanisms of nanowire growth, we performed thermal oxidation of copper to obtain nanowires at different times and temperatures. With detailed microstructural analysis of nanowires and oxide layers on which they grow as well as utilization of theoretical simulations, we obtained valuable information about growth of one dimensional metal oxide nanomaterials. Furthermore, mechanisms of anion exchange reactions were studied in the copper oxide – copper sulfide system. To achieve the oxide to sulfide transformations, copper oxide nanowires were subjected to plasma treatment with sulfur-containing gasses, which allowed us to study anion exchange in non-equilibrium plasma environments.