Fabrication of ZnO nanorods via a green hydrothermal method and their light driven catalytic activity towards the erasure of phenol compounds

• ZnO nanorods were fabricated via a green and surfactant-free hydrothermal method.
• Formation mechanism of the rod-like ZnO nanostructures was proposed.
• ZnO nanorods showed good photocatalytic performance for phenol degradation.
• (Nb2O5, Cr2O3)/ZnO nanocomposites exhibited excellent photocatalytic efficiency.

ZnO nanorods were prepared via a green and surfactant-free hydrothermal approach using ZnO powder and 30 vol% H2O2 aqueous solution. X-ray diffraction results revealed that the synthesized ZnO product was highly crystalline having hexagonal wurtzite structure. The band gap energy of ZnO nanorods was determined to be 3.28 eV using optical reflectance spectrum. The rod-like morphological features of ZnO nanostructures were observed from field-emission scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. The synthesized ZnO product showed an enhanced photocatalytic performance compared to the commercial TiO2 for the phenol degradation, which could be ascribed to its special structure feature. The Nb2O5/ZnO and Cr2O3/ZnO nanocomposites were also prepared and displayed enhanced photocatalytic efficiency after decorating metal oxide nanoparticles on the surface of ZnO nanorods.