Synthesis of Single-Crystalline Alkaline-Earth Metal Manganites Nanoribbons via Cation Exchange

Single-crystalline alkaline-earth metal manganites CaMn 3 O 6, SrMn 3 O 6– x and Ba 6 Mn 24 O 48 nanoribbons have been successfully synthesized by a facile ion-exchange approach based on molten-salt reaction between Na 0.44 MnO 2 nanoribbons and CaCl 2, SrCl 2, and BaCl 2 . All of these as-prepared nanoribbons are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). Taking the synthesis of single-crystalline SrMn 3 O 6– x nanoribbons as an example, we researched in detail the conversion process from Na 0.44 MnO 2 nanoribbons to SrMn 3 O 6– x nanoribbons. Our results indicate that Na 0.44 MnO 2 nanoribbons serve as the precursor template and the final products are obtained via ion-exchange reaction. Although there is a complete cation exchange, a change in stoichiometry, and a change in crystal structure, the morphology is nearly perfectly maintained. The synthetic method is thought to be a self-sacrificing templating route.