Synthesis of Highly Crystalline Single-Phase CoNb₂O₆ Nanofibers at Low Temperature and Their Structural Characterizations

We report the synthesis of highly crystalline single-phase CoNb₂O₆ nanofibers using an electrospinning method. Columbite niobate compounds (ANb₂O₆, A = Ca²⁺, Mg²⁺, Zn²⁺, Ni²⁺, Sn²⁺, and Co²⁺) are promising ceramic materials for many potential applications such as microwave devices and photocatalysts operating at room temperature. The fundamental characteristics including structural and electronic properties at room temperature, however, are not extensively studied at the moment. By combining the basic characterization utilizing electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and the first principles approach, we reveal the fundamental correlation between the lattice structure and the electronic structure of CoNb₂O₆. Our approach can readily be extended to studying other families of niobate ceramics made on the nanoscale for room-temperature applications.