An improved method for high photocatalytic performance of ZnAl_2O_4 spinel derived from layered double hydroxide precursor

摘要

A spinel structure of zinc aluminate (ZnAl_2O_4) 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 andtemperature have been investigated. The chemical composition, morphologies, phase structures, porous structures andphotocatalytic 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 spectroscopyin detail. The results of mesoporous α-ZnAl_2O_4 indicate that average crystallite size, total pore volume, and BET surfacearea obtain 9.3 nm, 0.337 cm~3/g, and 206.13 m~2/g, respectively. Moreover, zinc aluminate spinel shows well phase afterheating at 700 ℃ and LDHs structures were completely collapsed. The photocatalytic performances of α-ZnAl_2O_4 havebeen applied in p-nitrophenol reduction under visible light irradiation and required time at least 9 min. Finally, the newimproved method constructs an excellent material for pretreatment of liquid pollutants containing high-level concentrationat rapid treatment time.