Synthesis and photocatalytic study of SnO2/Zn2SnO4 nanocomposite prepared by sol–gel method using single source molecular precursor

Abstract

A single-source molecular precursor (SSP), ([Cl2Sn(μ-OtBu)2ZnCl2(bpy)]), was designed, developed, and subsequently used in a sol–gel process for the synthesis of SnO2/Zn2SnO4 nanocomposite at pH 9 adjusted by using a NaOH solution. The pre- and post-sintering IR spectra revealed the presence and absence, respectively, of the OH group. The powder XRD confirms the formation of the single crystalline ZnSn(OH)6 phase before sintering. However, the sintered product is composed of coupled oxides, i.e. the binary SnO2 and ternary Zn2SnO4. The scanning electron microscope (SEM) images taken after sonicating the SnO2/Zn2SnO4 powder show the macroporous texture of the powder. The uniformly sized particles are in two different morphological forms, i.e. cubic and spherical. The energy-dispersive x-ray (EDX) spectroscopy confirms the elemental composition of the SnO2/Zn2SnO4 nanocomposite (Zn:Sn:O = 2:2:6). The photocatalytic efficiency of the SnO2/Zn2SnO4 nanocomposite was tested by using the dye Sudan Red B a colorant used in red chilies. More than 82% of the dye degraded after 120 min of exposure to the UV light. The efficient photocatalytic activity is attributed to the better electron/hole pair separation which resulted from the coupling of Zn2SnO4 and SnO2 at the molecular level and produced efficient grain boundary interfaces.