Improved photocatalytic activity of SnO2–ZnAl LDH prepared by one step Sn4 + incorporation

• SnO2–ZnAl LDHs composites were successfully obtained by precipitation.
• The SnO2 was formed together with ZnAl LDH structure in one step.
• High photodegradation of phenol was achieved with Al:Sn of 0.7:0.3 mol%.
• The OH radical formation is the responsible of the high photoactivity.

SnO2–ZnAl LDH with a molar ratio Zn/(Al + Sn) 3/1 (Sn4 + contents 0.1–0.4 mol%) were prepared in one step by the co-precipitation method. The ZnAl LDH intercalated with carbonate ions and the composite of ZnAl LDH formed together with SnO2 were characterized by XRD, SEM, HRTEM and complementary spectroscopies such as FTIR, XPS and UV–Vis. The EDX and AAS was performed for the compositional analysis. The effect of the Sn4 + content on the opto-electronic properties of the dried SnO2–ZnAl LDH composites were evaluated on the phenol photodegradation under UV light irradiation. The mineralization degree of the photocatalysts was determined after 2 h of reaction by TOC analysis. The SnO2–ZnAl LDH composites that showed the highest photocatalytic activity were compared with ZnAl LDH sample impregnated with Sn4 + cations. The effect of the presence of the Zn5(CO3)2(OH)6 as precursor for the formation of the ZnAl LDH as well as the methodology of synthesis on the photocatalytic properties of the composites were studied. A possible mechanism of the OH radical formation and electron–hole charge separation in the improvement photocatalytic reaction were discussed.

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