ZnO decorated Sn3O4 nanosheet nano-heterostructure: a stable photocatalyst for water splitting and dye degradation under natural sunlight

Abstract

Herein, a facile hydrothermally-assisted sonochemical approach for the synthesis of a ZnO decorated Sn₃O₄ nano-heterostructure is reported. The phase purity of the nano-heterostructure was confirmed by X-ray diffraction and Raman spectroscopy. The morphological analysis demonstrated a nanosheet-like structure of Sn₃O₄ with a thickness of 20 nm, decorated with ZnO. The optical band gap was found to be 2.60 eV for the ZnO@Sn₃O₄ nano-heterostructure. Photoluminescence studies revealed the suppression of electron–hole recombination in the ZnO@Sn₃O₄ nano-heterostructure. The potential efficiency of ZnO@Sn₃O₄ was further evaluated towards photocatalytic hydrogen production via H₂O splitting and degradation of methylene blue (MB) dye. Interestingly, it showed significantly superior photocatalytic activity compared to ZnO and Sn₃O₄. The complete degradation of MB dye solution was achieved within 40 min. The nano-heterostructure also exhibited enhanced photocatalytic activity towards hydrogen evolution (98.2 μmol h⁻¹/0.1 g) via water splitting under natural sunlight. The superior photocatalytic activity of ZnO@Sn₃O₄ was attributed to vacancy defects created due to its nano-heterostructure.