Rapid microwave-assisted synthesis of one-dimensional silver–H 2Ti 3O 7 nanotubes

Abstract

The formation of silver hydrogen trititanate nanotubes, based on the controllable microwave-assisted hydrothermal nanocrystalline TiO 2 transition, was investigated by means of XRD, UV–vis–DRS, Raman, FESEM and HRTEM. The results show that the rapid formation of H-trititanate nanotubes is achieved by self-assemblage of silver nanoparticles in which the lamellar intermediates react with NaOH in hydrothermal conditions. The presence of Ag° nanoparticles in the precursor promotes rapid and more complete formation of layered H 2Ti 3O 7 nanotubes. After reacting for 4 h without subsequent thermal treatment, the inner diameters of the cylinder-like nanotubes are in the range of 3.6–4.0 nm, while their outer diameters are in the range of 7.6–8 nm. In addition, some straight nanotubes form bundles which are hundreds of nanometers in length. As-synthesized ultrathin nanotubes and crystalline precursors were evaluated by methyl orange dye (MOD) UV photo-oxidation. The complete degradation of MOD is achieved after 3.5 h of UV irradiation in the presence of silver–TiO 2 nanocomposites, resulting in 50% of dye mineralization.