Homogeneous distribution of nanosized ZnO in montmorillonite clay sheets for the photocatalytic enhancement in degradation of Rhodamine B

Abstract

Nanosized ZnO intercalated in montmorillonite (ZnO-MMT) was successfully prepared by two-step preparation: ion exchange and thermal treatment. It was found that the structure of the obtained composite was arranged in the house-of-cards structure with the homogeneous distribution of nanosized ZnO in the clay sheets, according to the XRD, SEM–EDX, TEM, XAS analyses. Importantly, as-obtained ZnO-MMT showed the small domains of crystalline ZnO with less particle aggregation. The particle size of ZnO defined by TEM was in the range of 1.8–3.0 nm. In addition, XAS results suggested the presence of short-range structural order in wurtzite ZnO crystalline. The photocatalytic activity of ZnO-MMT over Rhodamine B solution was remarkably enhanced with the normalized quantity of 8.4 mmol g−1 compared with a physical mixture of ZnO and montmorillonite (ZnO@MMT) (1.8 mmol g−1) and commercial ZnO (1.1 mmol g−1). This photocatalytic enhancement was attributed to the strong synergistic interaction of nanosized ZnO that was homogeneously embedded in the montmorillonite structure.