An improved method for high photocatalytic performance of ZnAl2O4 spinel derived from layered double hydroxide precursor

Abstract

A spinel structure of zinc aluminate (ZnAl2O4) particles provides a prospective material for photocatalytic applications. In this work, zinc aluminate spinel was prepared by an anion-exchange method derived from layered double hydroxides (LDHs) followed by thermal treatment. The mechanism, photoactivity, and effects of both anion substitute and temperature have been investigated. The chemical composition, morphologies, phase structures, porous structures and photocatalytic properties of samples were analyzed using thermogravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, gas sorption analysis, and ultraviolet–visible spectroscopy in detail. The results of mesoporous α-ZnAl2O4 indicate that average crystallite size, total pore volume, and BET surface area obtain 9.3 nm, 0.337 cm3/g, and 206.13 m2/g, respectively. Moreover, zinc aluminate spinel shows well phase after heating at 700 °C and LDHs structures were completely collapsed. The photocatalytic performances of α-ZnAl2O4 have been applied in p-nitrophenol reduction under visible light irradiation and required time at least 9 min. Finally, the new improved method constructs an excellent material for pretreatment of liquid pollutants containing high-level concentration at rapid treatment time.