Gallium-doped boehmite nanotubes and nanoribbons. A TEM, EDX, XRD, BET, and TG study

Gallium-doped boehmite nanostructures with varying Ga content have been prepared at low temperatures via a soft-chemistry route in the presence of poly(ethylene oxide) (PEO) surfactant. The effect of Ga content, hydrothermal temperature, and mixing procedures on the growth of boehmite nanostructures was systematically studied. The resultant boehmite nanostructures were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) microanalysis, X-ray diffraction (XRD), N-2 adsorption, and thermogravimetric analysis (TGA). Nanotubes with an average length of similar to 90 nm and internal and external diameters of 2-5 nm and 3-7 nm, respectively, were formed when the added Ga molar percentage was <= 5%; when the added Ga percentage was > 10%, an amorphous phase dominated the sample with a mixture of nanosheets, nanotubes, and nanoribbons being formed. Synthesis at slightly higher temperatures (120 degrees C) for an added Ga molar percentage of <= 5% resulted in longer nanotubes. For high-Ga-content boehmites, large crystals were formed when hydrothermally treated at 120 degrees C. The detailed characterization of the resultant Ga-doped boehmite nanostructures is presented.