Visible-light ZnO/In₂Cu₂O₅ nanocomposite with increased photocatalytic activity for degradation of malachite green

ZnO, In₂Cu₂O₅, and ZnO/In₂Cu₂O₅ have been synthesized using Gardenia jasminoides Ellis leaf extract, which contains essential secondary metabolites. Modification of ZnO with In₂Cu₂O₅ and their photocatalytic activity were explored for the first time under visible light irradiation. ZnO/In₂Cu₂O₅ nanocomposite possessed the decrement of band gap energy of ZnO to 2.84 eV, which was more susceptible to visible light. TEM analysis validated that the average size of ZnO/In₂Cu₂O₅ particles was approximately 50.45 nm, suggesting the formation of a composite material in a nanoscale. For the photocatalytic evaluation, 5 mg of ZnO/In₂Cu₂O₅ nanocomposite degraded malachite green dye for 120 min with an efficiency of 93.91 %. The photocatalytic properties of ZnO/In₂Cu₂O₅ were superior to those of ZnO and In₂Cu₂O₅. The notable increase in photocatalytic activity was due to the ZnO's narrower band gap and faster reaction rate. The present study demonstrates that visible-light ZnO-based materials with a small amount are efficient environmental photocatalysts, such as dye degradation.