A facile synthesis of hierarchical Sn₃O₄ nanostructures in an acidic aqueous solution and their strong visible-light-driven photocatalytic activity

Hierarchical tin(Ⅲ) oxide, Sn₃O₄, nanospheres were synthesized via hydrothermal reaction under strongly acidic ambient conditions. The morphology of Sn₃O₄ varied with decreasing pH. The prickly Sn₃O₄ nanospheres changed into Sn₃O₄ nanospheres covered with single-crystalline nanoplates having a high BET surface area of ca. 55.05 m²·g^–1 and a band gap of ca. 2.25 eV. Small amounts (0.05 g) of the hierarchical Sn₃O₄ nanostructures completely decomposed a 30% methyl orange (MO) solution in 100 mL deionized water within 15 min under one sun condition (UV + visible light). The Sn₃O₄ photocatalyst exhibited a fast decomposition rate of 1.73 × 10^-1 min^-1, which is a 90.86% enhancement relative to that of the commercially available P25 photocatalyst. The high photocatalytic activity of the hierarchical Sn₃O₄ nanostructures is attributed to its ability to absorb visible light and its high surface-to-volume ratio.