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

Abstract

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.