T ‐ZrO 2 prepared by a novel zirconium oxalate synthesised solvothermally

Abstract

In this work, the authors intentionally employ the oxalic acid (OA) to replace terephthalic acid to synthesise a novel zirconium oxalate under the similar reaction condition with UIO-66. The powder X-ray diffraction and thermal gravimetric analysis confirm that as-synthesised zirconium oxalate is a pure phase and oxalate serves as bridging ligand. Scanning electron microscope indicates that zirconium oxalate is aggregated together by several micrometres of needle-like crystals. After zirconium oxalate is calcined at 500°C, the product is the pure tetragonal zirconia (ZrO 2 ) with high crystallinity. The morphology and particle size of ZrO 2 are basically unmodified with a comparison with the zirconium oxalate. X-ray photoelectron spectroscopy reveals that the structural carbon acts as a phase transformation promoter to stabilise the tetragonal ZrO 2 .