A topochemical route to nondefect, three-dimensional perovskites from lamellar Dion-Jacobson and Ruddlesden-Popper precursors was demonstrated. The method involves reduction of one of the ions (in this case Eu3+) in the precursor phase and concomitant loss of oxygen. CsEu2Ti2NbO10, a three- layer Dion-Jacobson compound, was ion-exchanged to AEu2Ti2NbO10 (A = Na, Li) and reduced in hydrogen to form the SrTiO3-type perovskites AEu2Ti2NbO9. Similarly, K2Eu2Ti3O10, a three-layer Ruddlesden-Popper compound, underwent divalent ion exchange to form the Dion-Jacobson compounds A(II)Eu2Ti3O10 (A(II) = Ca, Sr) and M(II)Eu2Ti3O10 (M(II) = Ni, CU, Zn), which were reduced in hydrogen to perovskite-type A(II)Eu2Ti3O9 and M(II)Eu2Ti3O9, respectively. The A(II) and Eu2+ ions of A(II)Eu2Ti3O9 remain ordered, while A-site disordering occurs in the other perovskites. In all cases, the anisotropic texture of the layered precursors is retained in the product perovskite phase.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry