Controlling of morphology from nanoparticles to magnetic nanotubes and hollow nanorods are interesting for developing the photo-active materials and their applications in the field of photocatalysis and decontamination of aquatic effluents. In the current study, titanium dioxide nanoparticles and nanocomposites were prepared by different techniques to produce various morphologies. The nanoparticles of pure titanium dioxide were prepared by sol-gel technique. Magnetic nanotubes and hollow nanorods were prepared by combining titanium with di- and tri-valent iron through two stages: urea hydrolysis and solvent thermal technique. According to the Kirkendall effect, magnetic nanotubes were fabricated by unequal diffusion of Fe²⁺, Fe³⁺ and Ti⁴⁺ inside the nanocomposite to produce maghemite-titanian phase. In the same trend, hollow nanorods were synthesized by limited diffusion of both trivalent iron and tetravalent titanium producing amorphous structure of titanium iron oxides. The magnetic and optical properties showed that these nanotubes and hollow nanorods are magnetically active and optically more effective compared with titanium dioxide nanoparticles. Therefore, the Naphthol green B dye completely disappeared after 45 min of UV light irradiation in presence of the hollow nanorods. The kinetic study confirmed the high performance of the hollow nanorods for the photocatalytic degradation of Naphthol green B compared with titanium dioxide nanoparticles.

The present study has two aims, first to accelerate the degradation of pollutants by coating carbon nanotubes (CNTs) with nanoplatelets or nanocomposites of aluminum zinc oxides and second to fabricate an advanced photocatalyst. Accordingly, Zn‐Al layered double hydroxides (LDHs) were grown in the presence of functionalized CNTs during urea hydrolysis. The presence of CNTs led to the formation of LDH nanoplatelets, and TEM images showed that the CNTs were coated with nanoplatelets. The nanoplatelets were thermally treated to form nanocomposite‐coated CNTs. Raman spectra demonstrated the successful coating of CNTs with LDHs and nanocomposite. The coated CNTs were very effective in the photocatalytic degradation of industrial pollutants. A kinetics study demonstrated that the rate of photocatalytic degradation of green dye in the presence of CNTs coated with aluminum zinc oxide nanocomposite was five times faster than with the aluminum zinc oxide nanocomposite.

The present study describes a new strategy for modifying the structure of zinc oxide for removing colored pollutants from water after a few minutes of light irradiation.

Development of optical materials has attracted strong attention from scientists across the world to obtain low band gap energy and become active in field of solar energy. This challenge, which cannot be accomplished by the usual techniques, has overcome through the current study using non-conventional techniques. This study has used explosive reactions to convert non-optical alumina to series of new optical nanocomposites with very low band gap energy for the first time. In this trend, alumina nanoparticles were prepared and modified by explosive reactions using ammonium nitrate as a solid fuel. By using methanol or ethanol as a source of carbon species, three nanocomposites were produced indicating a gradual reduction of the band gap energy of alumina from 4.34 eV to 1.60 eV. These nanocomposites were obtained by modifying alumina via two different carbon species; core-shell structure and carbon nanotubes. This modification led to sharp reduction for the band gap energy to become very sensitive in sunlight. Therefore, these nanocomposites caused fast decolorization and mineralization of green dyes after illuminating in sunlight for ten minutes. Finally, it can be concluded that reduction of the band gap energy introduces new optical materials for developing optical nano-devices and solar cells.

Water pollution is one of the main challenges currently facing scientists around the world because of the rapid growth in industrial activities. On this basis, 2D nanolayered and nanohybrid structures, which are based on a ternary system of nickel–titanium–zinc, are considered favorable sources for designing effective nanocomposites for the photocatalytic degradation of industrial pollutants in a short period of time. These nanocomposites were designed by modifying two-dimensional nanolayers to produce a three-dimensional porous structure of multi-doped Ni/Ti-ZnO nanocomposites. Additionally, another additive was produced by constructing nanohybrids of nickel–titanium–zinc combined with a series of hydrocarbons (n-capric acid, myristic acid, stearic acid, suberic acid, and sebacic acid). Energy-dispersive X-ray spectrometry, X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and thermal analyses confirmed the growth of the nanolayered and nanohybrid materials in addition to the production of nanocomposites. The positive role of the dopants (nickel and titanium) in producing an effective photocatalyst was observed through a significant narrowing of the band gap of zinc oxide to 3.05–3.10 eV. Additionally, the high photocatalytic activity of this nanocomposite enabled the complete removal of colored dye from water after 25 min of UV radiation. In conclusion, this study proposes an unconventional approach for designing new optical nanocomposites for purifying water. Additionally, it suggests a novel supporting method for designing new kinds of nanohybrids based on multi-metals and organic acids.