Morphologically-tunable TiO2 nanorod film with high energy facets: green synthesis, growth mechanism and photocatalytic activity

A novel green synthesis strategy was developed to synthesize a film photocatalyst containing anatase TiO2 nanorods wholly dominated with {100} and {101} facets by employing a simple hydrothermal reaction in the presence of NaCl solution and hydrogen titanate nanosheet array film. The formation mechanism of the anatase TiO2 nanorods was deduced from X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations, which revealed that the highly reactive {100} facets were derived from the enhanced structural stability of hydrogen titanate induced by Na+ and selective adsorption of Cl- on the {100} facets of anatase TiO2 crystals. Photocatalytic performance has indicated that the TiO2 nanorods with {100} facet exposure exhibit much higher activities than that of rhombic nanoparticles with {101} facet exposure for the degradation of organic contaminants, which may be primarily ascribed to the high surface energy of {100} facets.