Nanocomposites based on copper and zinc oxides with various crystalline structures – synthesis, characterisation, and application

The article presents methods for synthesising nanocomposites of Cu and Zn with various crystalline structures, ranging from metallic oxides to solid solutions. Using physical vapour deposition and thermal oxidation, two types of nanocomposites were obtained: (I) Cu0.76Zn0.24 nanobrass covered with a porous ZnO nanofoam, and (II) CuO nanowires with a ZnO forming a core–shell nanostructure. The morphological and structural properties of the nanocomposites were analysed using scanning electron microscopy (SEM), transmission electron microscopy (TEM, HRTEM), and X-ray diffraction (XRD). The nanobrass with ZnO nanofoam composite exhibited strong gas-sensing activity. Its electrical resistance increased significantly when exposed to gases, showing responses of 158% for methane, 131% for hydrogen, and 91% for ammonia at 200 °C, with full reversibility upon air flushing. The CuO-ZnO nanowire composite demonstrated high photocatalytic efficiency. These findings highlight the potential of the developed nanocomposites for applications in gas sensing and photocatalytic environmental treatment.