A Fresh Perspective on the Impact of ZnTiO(3) Coupling on the Microstructure and Photocatalytic Properties of TiO(2) Fabricated at Varied Temperatures

ZnTiO(3)/TiO(2) composite photocatalysts were synthesized via the sol–gel technique, and the impact of varying heat treatment temperatures (470, 570, 670 °C) on their crystalline arrangement, surface morphology, elemental composition, chemical state, specific surface area, optical characteristics, and photocatalytic efficacy was systematically investigated. The outcomes revealed that, as the temperature ascends, pure TiO(2) undergoes a transition from anatase to rutile, ultimately forming a hybrid crystal structure at 670 °C. The incorporation of ZnTiO(3) engenders a reduction in the TiO(2) grain dimensions and retards the anatase-to-rutile phase transition. Consequently, the specimens manifest a composite constitution of anatase and ZnTiO(3). In contrast, for pure TiO(2), the specimen subjected to 670 °C annealing demonstrates superior photocatalytic performance due to its amalgamated crystal arrangement. The degradation efficacy of methylene blue (MB) aqueous solution attains 91% within a 60-min interval, with a calculated first-order reaction rate constant of 0.039 min(−1). Interestingly, the ZnTiO(3)/TiO(2) composite photocatalysts exhibit diminished photocatalytic activity in comparison to pristine TiO(2) across all three temperature variations. Elucidation of the photocatalytic mechanism underscores that ZnTiO(3) coupling augments the generation of photogenerated charge carriers. Nonetheless, concurrently, it undermines the crystalline integrity of the composite, yielding an excess of amorphous constituents that impede the mobility of photoinduced carriers. This dual effect also fosters escalated recombination of photogenerated charges, culminating in diminished quantum efficiency and reduced photocatalytic performance.