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

A single-source molecular precursor (SSP), ([Cl₂Sn(μ-O^tBu)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.