Fabrication of novel SnWO4/ZnO using Muntingia calabura L. leaf extract with enhanced photocatalytic methylene blue degradation under visible light irradiation

In this study, SnWO4/ZnO heterostructure has been successfully constructed using Muntingia calabura L. leaf extract (MCE). We conducted phytochemical tests to qualitatively detect the presence of secondary metabolites such as alkaloids, saponins, flavonoids, and tannins, which play an essential role in the formation of SnWO4/ZnO. The photocatalytic activities of pristine SnWO4, pristine ZnO, and SnWO4/ZnO heterostructure were evaluated for the degradation of methylene blue (MB) under visible light irradiation. To investigate the photocatalytic activity of SnWO4/ZnO heterostructure in the visible region, the adsorption effect of SnWO4/ZnO was also studied. SnWO4/ZnO heterostructure shows the highest degradation percentage of 82.86% within 120 min compared to pristine SnWO4 and ZnO, which exhibit the degradation percentage of 69.48 and 40.41%, respectively. The enhanced photocatalytic of MB degradation is attributed to the formation of SnWO4/ZnO heterostructure as a result of the decreased optical bandgap from 3.06 to 2.68 eV due to the low recombination rate of photogenerated electron-hole pairs. SnWO4/ZnO shows a remarkable photocatalyst for dyes degradation with remarkable stability after four consecutive cycles. Importantly, this work demonstrates a simple ecofriendly, and low-cost green synthesis method to produce SnWO4/ZnO with excellent photocatalytic activity and stability for dyes degradation under visible light irradiation.

Automated summary

In this study, a SnWO4/ZnO heterostructure was successfully constructed using Muntingia calabura L. leaf extract, demonstrating significant photocatalytic degradation of methylene blue under visible light irradiation with excellent stability. The formation of the heterostructure led to enhanced photocatalytic activity attributed to decreased optical bandgap and low recombination rate of photogenerated electron-hole pairs, showing potential for ecofriendly and cost-effective dye degradation applications.