Enhanced Visible‐Light Photocatalysis via TiO ₂ ‐Based Ni‐Doped ZnO Nanocomposites for Sustainable Dye Degradation

In the present work, 5% Ni‐doped ZnO/TiO 2 nanocomposites were synthesized via a coprecipitation method to investigate their potential for sunlight‐assisted photocatalytic degradation of RhB dye. X‐ray diffraction analysis confirmed a hexagonal crystal structure with an increase in crystallite size upon the incorporation of TiO 2 and Ni into the ZnO lattice. Morphological studies revealed uniformly distributed, well‐separated, and nearly spherical particles with an average size of 36.4 nm. Raman spectroscopy indicated enhanced structural defects and the presence of local surface distortions in the Ni‐doped samples. The 5% Ni‐doped ZnO/TiO 2 nanocomposites exhibited a remarkable photodegradation efficiency of 93.3% for RhB dye under 120 min of natural sunlight irradiation, outperforming both pure ZnO and TiO 2 ‐based ZnO counterparts. Scavenger analysis confirmed that hydroxyl radicals (•OH) are the major reactive species responsible for the photocatalytic degradation process. The enhanced photocatalytic activity can be attributed to the synergistic effects of Ni doping, increased crystallite size, and defect‐induced active sites, making the material a promising candidate for environmental remediation applications.