Facile synthetic route to transition metal oxyfluorides via reactions between metal oxides and PTFE

Inorganic oxyfluorides have significant importance in the development of new functionalities for energy production and storage, photonics, catalysis, etc. In order to explore a simple preparation route that avoids the use of toxic HF or F2 gas as a reaction reagent, we have employed polytetrafluoroethylene (PTFE). Five oxyfluorides including Nb5O12F, Nb3O7F, Ta3O7F, TaO2F, and Mo4O11.2F0.8 were synthesized by reactions between PTFE and transition metal oxides in sealed quartz ampules. The reaction mechanism was studied by means of gas analysis, which detected SiF4 as a main product gas during the reaction. A possible reaction mechanism between the PTFE and transition metal oxides is discussed.