Superoxide (•O2-) radical species driven type II TiO2/g-C3N4 heterojunction photocatalyst for RhB dye degradation

The photocatalysts possess prime importance from sustainable environment view point since they decompose detrimental substances. In this work, we report a type II heterojunction of titanium dioxide/graphitic carbon nitride (TiO2/g-C3N4) photocatalysts for degradation of rhodamine B (RhB) dye under UV-Visible light irradiation. The pristine TiO2 and g-C3N4 materials are prepared by hydrothermal and thermolysis methods, respectively. The heterojunction photocatalysts, i.e. TiO2/g-C3N4 are synthesized with different weight% (wt%) loadings of TiO2 over g-C3N4 by hydrothermal method. The physico-chemical properties of all photocatalysts are analysed by different characterization techniques. Compared with the pristine phase of TiO2 and g-C3N4, the heterojunction photocatalysts showed improved efficiency due to effective charge transfer between TiO2 with g-C3N4 and enhanced visible light harvesting. Owing to effective superlative light absorption and generation of the large number of electron-hole pairs, suppression of recombination centres, formation of active species (specially center dot O-2(-)), etc., 5 wt% loaded TiO2/g-C3N4 photocatalyst demonstrated superior performance. Moreover, 5 wt% loaded TiO2/g-C3N4 photocatalyst exhibited recyclability with high activity (92% after 4 cycles) and thus, we believe it possesses potential for use in industrial water treatment.