Construction of novel ZnTiO₃/g-C₃N₄ heterostructures with enhanced visible light photocatalytic activity for dye wastewater treatment

In this study, the crystalline and homogenous ZnTiO₃ particles were first synthesized in KCl-NaCl eutectic chloride salts at 700–850 °C. Then the ZnTiO₃ was successfully loaded onto g-C₃N₄ sheets to form ZnTiO₃/g-C₃N₄ composites during the polymerization of melamine. Compared with pure g-C₃N₄, ZnTiO₃/g-C₃N₄ composites have shown an obvious red shift phenomenon and enhanced light harvesting ability in the spectra range of 200–800 nm as well as much lower recombination rate of the photogenerated charge carriers. The ZTOCN1-800 samples exhibited a 1.69 times specific surface area as pure g-C₃N₄ by BET analysis, and a 76% degradation efficiency for methyl orange (MO) under visible light irradiation in 180 min, about 13 times as that of pure ZnTiO₃ and 3 times as that of pure g-C₃N₄. Moreover, The ZTOCN1-800 samples achieved complete degradation of MB and RhB under visible light irradiation within 90 min. This is attributed to the intimate heterostructure interface between g-C₃N₄ and ZnTiO₃ due to ZnTiO₃ particles intercalation into the g-C₃N₄ sheets, which reduced the self-aggregation of the g-C₃N₄ sheets and greatly facilitated the charge transfer from photo-excited g-C₃N₄ to ZnTiO₃. These were demonstrated by XRD, SEM, EDX, TEM, UV–Vis, PL and photoelectrochemical analysis.