Synthesis Technology Of Micro-structured Niobium Compounds Via Wet Chemical Routes

Niobium compounds have been drawing intensive interests due to their outstanding physical and chemical properties, and nanomaterials always show a strong correlation between their function and intrinsic factors, such as chemical compositions, crystal structures and morphologies. Therefore, design of novel chemical strategy for microstructure and study of environment-friendly mild synthetic technology will open up new opportunities in development of niobium-based science and technology. Mainly focusing on Nb2O5, a series of wet-chemistry route was adopted to fabricate multiple low-dimensional structures. The main points are summarized herein:A phase-transformation method was developed to synthesize niobates with different nanostructures. (NH4)3NbO4F4 and (NH4)3NbO8 were selectively prepared by changing the added content of NH3·H2O in the mixed solution of oxofluoroniobic acid and H2O2. The obtained peroxy niobates were respectively employed as precursors for the synthesis of F-doped Nb2O5 nanotubes and H2Nb2O6 hollow spheres under solvothermal conditions. Pure Nb2O5 nanotubes and hollow spheres were further obtained through moderate calcination. Mechanism of morphology evolution was also investigated.A general template-free mild method has been successfully designed to prepare one-dimensional niobium oxide. Formamide acts as solvent and chelating agent in the current solvothermal route, which affects nucleation and growth of Nb2O5 rod powder through thermodynamic and kinetic control. This strategy is extended to prepare Nb2O5 rod arrays on the niobium substrate through heterogenerous reaction. Nanotube arrays were further prepared by moderate chemical etching.