W18O49 Nanowhiskers Decorating SiO2 Nanofibers: Lessons from In Situ SEM/TEM Growth to Large Scale Synthesis and Fundamental Structural Understanding

0580771 - ÚPT 2025 RIV US eng J - Journal Article
Kundrát, V. - Bukvišová, K. - Novák, L. - Průcha, Lukáš - Houben, L. - Zálešák, J. - Vukusic, A. - Holec, D. - Tenne, R. - Pinkas, J.
W18O49 Nanowhiskers Decorating SiO2 Nanofibers: Lessons from In Situ SEM/TEM Growth to Large Scale Synthesis and Fundamental Structural Understanding.
Crystal Growth & Design. Roč. 24, č. 1 (2024), s. 378-390. ISSN 1528-7483. E-ISSN 1528-7505
Institutional support: RVO:68081731
Keywords : electrospinning * tungsten oxide * nanowhiskers * nanofibers * W18O49
OECD category: Inorganic and nuclear chemistry
Impact factor: 3.8, year: 2022
Method of publishing: Open access
https://pubs.acs.org/doi/10.1021/acs.cgd.3c01094

Tungsten suboxide W18O49 nanowhiskers are a material of great interest due to their potential high-end applications in electronics, near-infrared light shielding, catalysis, and gas sensing. The present study introduces three main approaches for the fundamental understanding of W18O49 nanowhisker growth and structure. First, W18O49 nanowhiskers were grown from gamma-WO3/a-SiO2 nanofibers in situ in a scanning electron microscope (SEM) utilizing a specially designed microreactor (mu Reactor). It was found that irradiation by the electron beam slows the growth kinetics of the W18O49 nanowhisker, markedly. Following this, an in situ TEM study led to some new fundamental understanding of the growth mode of the crystal shear planes in the W18O49 nanowhisker and the formation of a domain (bundle) structure. High-resolution scanning transmission electron microscopy analysis of a cross-sectioned W18O49 nanowhisker revealed the well-documented pentagonal Magnéli columns and hexagonal channel characteristics for this phase. Furthermore, a highly crystalline and oriented domain structure and previously unreported mixed structural arrangement of tungsten oxide polyhedrons were analyzed. The tungsten oxide phases found in the cross section of the W18O49 nanowhisker were analyzed by nanodiffraction and electron energy loss spectroscopy (EELS), which were discussed and compared in light of theoretical calculations based on the density functional theory method. Finally, the knowledge gained from the in situ SEM and TEM experiments was valorized in developing a multigram synthesis of W18O49/a-SiO2 urchin-like nanofibers in a flow reactor.
Permanent Link: https://hdl.handle.net/11104/0349528