Low-Temperature Solvothermal Approach to the Synthesis of La4Ni3O8 by Topotactic Oxygen Deintercalation

A chimie douce solvothermal reduction method is proposed for topotactic oxygen cleintercalation of complex metal oxides. Four different reduction techniques were employed to qualitatively identify the relative reduction activity of each including reduction with H-2 and NaH, solution based reduction using metal hydrides at ambient pressure, and reduction under solvothermal conditions. The reduction of the Ruddlesden-Popper nickelate La4Ni3O10 was used as a test case to prove the validity of the method. The completely reduced phase La4Ni3O8 was produced via the solvothermal technique at 150 degrees C-a lower temperature than by other more conventional solid state oxygen deintercalation methods.