Microstructure and Materials Characterization of Sol-Gel Synthesized ZrO2 Systems

Abstract

The roles of pH and thermal treatment on the microstructures of sol-gel synthesized mesoporous ZrO₂ systems have been investigated. In order to control the crystal structures and particle sizes of the final products, the pH values of the reaction mixtures were controlled between 5 and 12 followed by calcination at temperatures ranging from 450 to 1000 °C. The microstructures of the zirconia systems were then examined by XRD, TEM, TGA, UV-visible DRS and nitrogen physisorption study analyses. It was found that pH values and calcination temperatures have significant influence on the crystallization temperature, phase transformation and particle size of the ZrO₂ systems. Pure tetragonal and monoclinic ZrO₂ crystals or a mixture of tetragonal and monoclinic ZrO₂ crystals with controlled particle size could readily be yielded by maintaining the pH values and the calcination temperatures. This study therefore elucidates a facile approach to yielding sol-gel synthesized metal oxide nanoparticles with controlled phase and particle size.

Keywords: Microstructure; Zirconia systems; Sol-gel process; Phase transformation.