Enhanced photocatalytic degradation and hydrogen production activity of in situ grown TiO2 coupled NiTiO3 nanocomposites

A UV and visible light responsive binary phase TiO2 coupled NiTiO3 nanocomposites were prepared by a facile co-precipitation method followed by calcination at elevated temperatures. The phase structure, morphology and optical properties of the nanocomposite were characterized by XRD, FE-SEM, HRTEM, UV-vis DRS, EIS and Raman spectra. XRD and Raman spectrum shows that between 650 °C and 850 °C, a phase transition takes place. FE-SEM and TEM analysis revealed that during the synthesis, growth of cylindrical shaped amorphous NiTiO3 took place and upon calcinations; it transforms into highly crystalline interlinked chain type morphology. A noticeable three distinct optical transitions corresponding to 3.1, 2.5 and 2.27 eV were observed by UV-vis diffuse reflection spectroscopy (DRS). The TiO2/NiTiO3 nanocomposite was used for Tetracycline and RhB photodegradation, and photocatalytic water splitting activity under UV-vis light irradiation. The results of this study showed that the nanocomposites calcined at 750 °C exhibit significantly higher photocatalytic degradation and water splitting activity. Based on the experimental results, an n-n heterojunction charge carrier transfer and separation mechanism is proposed.