ZnO plates synthesized from the ammonium zinc nitrate hydroxide precursor

Abstract

ZnO assembled hexagonal or porous rectangular plates were synthesized from the decomposition of a new precursor, ammonium zinc nitrate hydroxide (NH₄Zn₃(OH)₆NO₃), through a facile solvothermal route assisted by Poly(styrene sulfonic acid) sodium salt (PSS). XRD, BET surface area measurements, SEM, HRTEM and TG-DSC were used to describe the as-prepared products and understand the phase transformation. Our results indicate that the morphology of the ZnO plates is dependent strongly on the decomposition process of the precursor. By directly heating NH₄Zn₃(OH)₆NO₃, porous ZnO plates were obtained due to the thermal decomposition of the precursor. Using the same precursor under the solvothermal reaction, however, the final product is hexagonal ZnO plates. The growth mechanism of ZnO plates formed in different synthetic routes was proposed. Photoluminescence (PL) and photocatalytic properties of the as-prepared ZnO with different morphologies were studied. Porous ZnO plates showed three emission peaks, which may be induced by its microstructure and defect centres, and the porous ZnO showed the improved photocatalytic activity for photoreduction of CO₂.