Biogenic fabrication of ZnO–SnO2 nanocomposite for effective photodegradation of toxic industrial dyes

The preparation of eco-friendly, cost-effective, reusable effective photocatalyst is necessary for remediation of persistent various pollutants. To address this encounter, a unique green method was used to prepare ZnO–SnO2 nanocomposite (NC) using Syzygium cumini leaf (SC) extract. The ZnO–SnO2 was characterized by TEM, FT-IR, XRD, XPS, BET and UV–Vis techniques. The size of ZnO–SnO2 NCs is in the range of 10–15 nm with spherical morphology is confirmed by TEM analysis. By XRD, it was established that the crystal structure of ZnO is hexagonal wurtzite and SnO2 is tetragonal. The BJH plot shows that the prepared ZnO–SnO2 NCs are mesoporous with high surface area (115.42 m2/g). The FT-IR peaks at 523 and 646 cm−1 designate the formation of Zn–O and O–Sn–O bonding, which confirms the formation of ZnO–SnO2 NCs. The increase in ZnO content in the SnO2, the band gap decreases. The photocatalytic activity of ZnO–SnO2 NCs is applied for the degradation of methyl orange (MO) and methylene blue (MB) dyes under UV–Vis light. The ZnO–SnO2 NCs exhibit the degradation efficiencies of 99.5 (MO) and 99.3