Drastic improvement in catalytic, optical and visible-Light photocatalytic behavior of cobalt and nickel doped TiO₂ nanopowder

The titanium dioxide composites with cobalt (Co), nickel (Ni) and cobalt-nickel (Co-Ni) doped nanoparticles were synthesized using a sol-gel route. The structural, morphological, and physicochemical properties of mixed Co and Ni (3%) to TiO₂ were characterized by XRD, FTIR, SEM, DSC-TGA, VSM, Raman and UV–vis spectroscopy. XRD pattern revealed TiO₂ tetragonal-anatase phase and has confirmed a significant effect on crystallinity and particle size upon doping. The presence of strong chemical bonding and functional group at the interface of TiO₂ nanoparticles was confirmed by FTIR. The increase in absorption range with different doped materials was recorded by UV–vis spectroscopy. The saturation magnetization (M_S) was higher for TiO₂ relative to doped materials. However, the thermal stability of the samples at high temperature (0 to 1000 °C) was monitored using DSC-TGA. The morphology of synthesized undoped and doped TiO₂ nanoparticles showed agglomerations of nanomaterials was examined using SEM. The synthesized nanomaterials have been successfully applied as nanocatalyst in degradation of methylene blue. Co-Ni doped TiO₂ nanoparticles an impressive catalytic performance in the presence of reducing agent NaBH₄. This increase is attributed to augmentation of light absorption in the visible range with doping. Thus, Co:Ni:TiO₂ in the presence of NaBH₄ can be a promising photocatalyst in the field of wastewater treatment. (paper)