Zn,Al hydrotalcites calcined at different temperatures: Preparation, characterization and photocatalytic activity in gas–solid regime

Abstract

Layered double hydroxides (LDH) containing zinc and aluminium within the brucite-like layers and carbonate as the interlayer anion have been used as precursors for the preparation of mixed metal oxides by calcination. Zinc oxide and the ZnAl 2O 4 spinel were formed with different degree of crystallinity depending of two parameters, i.e., the Zn 2+/Al 3+ molar ratio and the calcination temperature (500–800 °C) of the LDH precursor. A pure spinel phase was obtained to remove ZnO upon a basic post-treatment in NaOH solution of the samples calcined at 800 °C. All the samples were tested for the photodegradation of 2-propanol in gas–solid regime. All the samples resulted active as heterogeneous photocatalysts. The photocatalytic activity increased by increasing the Zn 2+/Al 3+ molar ratio and the calcination temperature of the solids.