Low-Temperature Nanoparticle-Directed Solid-State Synthesis of Ternary and Quaternary Transition Metal Oxides

Abstract

Ternary and quaternary transition metal oxides, which offer a wide variety of important physical properties, are traditionally synthesized using high-temperature reactions that often require several days of heating. A new nanoparticle-directed approach for the rapid low-temperature synthesis of nanocrystalline bulk-scale ternary and quaternary transition metal oxides has been developed. Readily available metal oxide nanoparticles can serve as a robust toolkit of highly reactive reagents, which can be mixed in solution in known ratios to form nanomodulated precursors and rapidly transformed, at relatively low temperatures, into more complex oxides. This approach is initially demonstrated for pyrochlore-type Y2Ti2O7 and Eu2Ti2O7 using XRD, DSC, and TEM to monitor the reaction. A nanocomposite of Y2O3 and TiO2 nanoparticles transforms into nanocrystalline Y2Ti2O7 within 2 h of heating to 700 °C, and Eu2Ti2O7 forms within 2 h of heating a nanocomposite of Eu2O3 and TiO2 nanoparticles to 800 °C. NiTiO3, CoTiO3...