Mixed-phase structural characterization of urchin-like CuO/Cu₂O nanostructures

In this study, urchin-like CuO/Cu₂O mixed-phase nanostructures were synthesized via a simple surfactant-assisted approach, where the surfactant regulated the nucleation and anisotropic growth, leading to a hierarchical morphology with radially arranged nanoneedles. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses verified the coexistence of CuO and Cu₂O phases within individual microspheres. High-resolution transmission electron microscopy (HRTEM) revealed well-defined lattice fringes assigned to Cu₂O, while XRD, XPS, SAED, and EDS analyses collectively suggest the coexistence of CuO and Cu₂O phases within the hierarchical microspheres. Energy-dispersive spectroscopy (EDS) mapping and line-scan profiles indicated a gradual compositional variation of copper and oxygen from the core to the surface region. Furthermore, in situ electron-beam irradiation demonstrated structural densification of the urchin-like architecture, providing insight into its structural stability. These results offer fundamental understanding of mixed-phase copper oxide formation and highlight their potential for high-surface-area functional materials.