Preparation of LaTiO 2 N Using Hydrothermally Synthesized La 2 Ti 2 O 7 as a Precursor and Urea as a Nitriding Agent

A facile method was successfully developed to prepare perovskite‐type metal oxynitrides, LaTiO 2 N, from La 2 Ti 2 O 7 as a precursor in an atmosphere of N 2 . Urea was employed as a solid‐state nitriding agent, instead of gaseous NH 3 , to increase the safety of the reaction. The hydrothermally prepared La 2 Ti 2 O 7 precursor had a nanosheet morphology and contained La(OH) 3 as a by‐product. Through the optimization of reaction conditions including heat‐treatment temperature and content of urea, single‐phase LaTiO 2 N could be obtained. In addition, we revealed that the La(OH) 3 present in the La 2 Ti 2 O 7 precursor played an important role in the nitriding process using urea. La 2 O 2 CN 2 was generated by the reaction of La(OH) 3 with the thermal decomposition products of urea at the medium temperature range. This indicated that the NH 3 gas released from the thermal decomposition of urea did not directly cause nitridation of the La 2 Ti 2 O 7 precursor.