A Facile Synthetic Approach for TiO₂@NiO Core‐shell Nanoparticles using TiO₂@Ni(OH)₂ Precursors and their Photocatalytic Application

Abstract The current study presents a simple and an efficient chemical method for the synthesis of TiO₂@NiO core‐shell nanoparticles (CSNPs) as photocatalyst for effective degradation of rhodamine B (RhB) in an aqueous solution upon sunlight irradiation. First, TiO₂ spheres were synthesized using a wet chemical method. Then, TiO₂@Ni(OH)₂ precursors were prepared via homogeneous precipitation and TiO₂@NiO core‐shell nanoparticles were obtained on calcination of the precursors. The synthesized precursors and the TiO₂@NiO CSNPs were analyzed using XRD, FT‐IR, FESEM and DRS. XRD data shows the presence of both TiO₂ and NiO phases in the TiO₂@NiO samples. FE‐SEM and TEM analyses confirm coating of NiO NPs on TiO₂ spheres with varying shell thickness (40 nm to 170 nm). Optical studies reveal that TiO₂@NiO CSNPs possess band gap of about 3.7 eV. Photoluminescence (PL) results show lower recombination rate of e⁻ and h⁺ pairs in the TiO₂@NiO CSNPs. XPS studies confirm the presence of different elements in the TiO₂@NiO CSNPs. Magnetic investigations reveal ferromagnetic behavior of the core‐shell NPs at 5 K. The TiO₂@NiO CSNPs were explored as photocatalyst for the degradation of rhodamine B in water under natural sunlight. The TiO₂@NiO CSNPs exhibit better photocatalytic activity compared to TiO₂ and NiO nanoparticles.