Diverse Morphologies of Nb₂O₅ Nanomaterials: A Comparative Study for the Growth Optimization of Elongated Spiky Nb₂O₅ and Carbon Nanosphere Composite

Abstract

Controlled synthesis and design of nanomaterials with intricate morphologies and active phases offer new prospects in harnessing their unique chemical and physical properties for various applications. Herein, a facile and efficient hydrothermal approach is reported for obtaining various complex Nb2O5 nanostructures, including thin sheets, thick flakes, spiky and elongated spiky sea urchin morphologies using urotropin as a growth‐directing and hydrolyzing agent in various mixed and pure solvents. The detailed structural and chemical composition, surface morphology and crystallinity of as‐synthesized Nb2O5 nanostructures are presented. The urotropin concentration, reaction time, and water‐ethanol solvent mixture play a critical role for obtaining the elongated spiky sea urchin morphologies. The spiky Nb2O5 structures show a pseudohexagonal phase with less urotropin content, while thin sheets are obtained with a higher urotropin concentration and are primarily amorphous. These structures undergo transformation in their crystal phase and morphologies during calcination at higher temperatures revealing the active role of urotropin in stabilizing them. A composite of spiky sea urchin Nb2O5‐carbon nanospheres (suNb2O5‐CNS) is achieved by in‐situ growth of Nb2O5 in the presence of CNS without compromising on morphology, phase, and crystallinity. suNb2O5‐CNS composite is shown to possess higher charge storage capacity compared to its constituents for supercapacitor applications.