Synthesis of ZrP2O7 by hydrothermal reaction and post-calcination

A new method of synthesis of single phase ZrP2O7 was studied using hydrothermal reaction of amorphous ZrO(OH)2 with H3PO4 and subsequent air calcination. The reaction steps to ZrP2O7 were analyzed by means of XRD, TG/DTA and FT-IR. The hydrothermal reaction at 200°C for 18 h yielded well-crystallized tetraphosphate, Zr3(PO4)4, loaded with unreacted H3PO4. Upon heating above 500°C, the mixture caused the stoichiometric reaction to form ZrP2O7, but impurities such as ZrO2 and Zr2P2O9 were not formed. TEM observation confirmed that ZrP2O7 after calcination at 900°C consisted of crystallites in size of several ten nanometers.