Hydrothermal synthesis, characterization and photocatalytic properties of cu ₂po ₄oh with hierarchical morphologies

Cu ₂PO ₄OH with various hierarchical morphologies were synthesized using a hydrothermal method by simple adjusting the pH value and temperature. The prepared powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, fourier-transform infrared spectroscopy (FT-IR), and UV-Vis diffuse reflectance spectroscopy. It was found that overall morphologies of Cu ₂PO ₄OH were varied from micro-rods to walnut-like microspheres as increasing the initial solution pH value and their size of the assembled crystallites was smaller at lower temperature. From the FT-IR and Raman analysis, the incorporation of the hydroxyl ions (OH-) into the crystal structure plays important roles to their crystallization process, and finally affects their morphologies. Moreover, the optical absorption properties of the Cu ₂PO ₄OH were strongly related to their morphologies. The photocatalytic activity of Cu ₂PO ₄OH with various morphologies was also investigated via the degradation of rhodamine B (RhB) dye solution under visible light irradiation (λ > 410 nm). The walnut-like microsphere assembled with nanoparticles exhibited higher photocatalytic activity due to the higher optical absorption as well as a higher surface area.