Synthesis of Composite Zn2SnO4/SnO2 as Photocatalyst Materials by Means of Sonochemical Treatment and Its Electronic Structure

Abstract

Metal oxide semiconducting compounds have potential application as photocatalyst materials to decompose many types of dyes and pollutants in the water. Zn2SnO4 and SnO2 are semiconducting materials that have photocatalytic properties and the properties of those two semiconducting materials in the composite form have been studied. Metal oxide compounds of Zn2SnO4 and SnO2 have been prepared through sonochemical methods using ZnCl2 and SnCl4.5H2O as precursors. After sonication and heat treatment at 1000 °C, we could obtain Zn2SnO4 and SnO2 compound in the sample as confirmed by x-ray diffraction measurement. The volume fraction of Zn2SnO4 and SnO2 phases in the sample were found to be at 60 % and 40 %, respectively. The absorption spectra revealed that the band gap of the composite materials is 3.7 eV. This material could degrade all of the methylene blue with concentration of 6.0 x 10-6 M in 120 minutes. The band structure calculation revealed that the comparable band gap values are found for Zn2SnO4 and SnO2 compounds. However, the absorption edges for those compounds are slightly different, with absorption edge at 3.2 eV for SnO2 and 3.6 eV for Zn2SnO4, respectively.