Abstract: ZnO nanotubes were synthesized by the hydrothermal method using sodium dodecyl sulfate as the template, and ZnO nanopartides were prepared with urea and ZnSO₄ as raw materials. The optical properties and photocatalytic activity of ZnO nanotubes and nanoparticles were studied, and the samples were characterized by transmission electron microscopy, X-ray diffraction, photoluminescence spectroscopy, Raman spectroscopy, specific surface area determination, Fourier transform infrared spectroscopy, and ultraviolet-visual diffuse reflection spectroscopy. The ZnO nanotubes had larger specific surface area than the ZnO nanoparticles. The absorption peak of ZnO nanotubes began to appear at λ ≈ 650 nm, but the ZnO nanoparticles nearly had no absorptive capacity in the visible band. ZnO nanotubes and nanoparticles can degradate methyl orange under ultraviolet light, and the catalytic activity of ZnO nanotubes was greater than that of ZnO nanoparticles. With the increase in the catalyst amount and illumination time, the degradation rate of methyl orange increased. Increasing the methyl orange concentration reduced the degradation rate.

Key words: zinc oxide, nanotube, nanoparticle, methyl orange, degradation, photocatalytic activity