Synthesis and characterization of Nb₂O₅@C core-shell nanorods and Nb₂O₅ nanorods by reacting Nb(OEt) ₅ via RAPET (reaction under autogenic pressure at elevated temperatures) technique

The reaction of pentaethoxy niobate, Nb(OEt)₅, at elevated temperature (800 °C) under autogenic pressure provides a chemical route to niobium oxide nanorods coated with amorphous carbon. This synthetic approach yielded nanocrystalline particles of Nb₂O₅@C. As prepared Nb₂O₅@C core-shell nanorods is annealed under air at 500 °C for 3 h (removing the carbon coating) results in neat Nb ₂O₅ nanorods. According to the TEM measurements, the Nb₂O₅ crystals exhibit particle sizes between 25 nm and 100 nm, and the Nb₂O₅ crystals display rod-like shapes without any indication of an amorphous character. The optical band gap of the Nb₂O₅ nanorods was determined by diffuse reflectance spectroscopy (DRS) and was found to be 3.8 eV.