Low temperature synthesis of τ-zirconium hydrogenophosphate [τ-Zr(HPO4)2] and a new sodic form obtained by ion exchange

A new method for the synthesis of 3-D τ-zirconium hydrogenophosphate (TZP) was developed using solid-state reactions at low temperature and atmospheric pressure in a nitrogen atmosphere in a two-hour reaction time. The characterization of the compound was performed using X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, differential scanning calorimetric, thermochemical analysis and X-ray photoelectron spectroscopy. A sodic form of the compound obtained by the immersion of TZP in a sodium hydroxide solution was characterized using the same techniques along with neutron activation analysis. The XPS spectra confirm the binding energy value for sodium–oxygen, and the XRD diffraction reveals the formation of a new sodium compound.

Graphical abstractDRX, XPS and MEB of τ-zirconium hydrogenophosphate and its sodic form on the surface of TZP.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► New method for the syntheses of 3-D τ-zirconium hydrogenophosphate (TZP). ► A sodic form of the TZP was obtained by the immersion of TZP in a sodium hydroxide. ► The sodium compound is only formed on the TZP surface.