Mechanism of WS<sub>2</sub> Nanotube Formation Revealed by <i>in Situ</i>/<i>ex Situ</i> Imaging
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F24%3APU151394" target="_blank" >RIV/00216305:26620/24:PU151394 - isvavai.cz</a>
Result on the web
<a href="https://pubs.acs.org/doi/10.1021/acsnano.4c01150" target="_blank" >https://pubs.acs.org/doi/10.1021/acsnano.4c01150</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acsnano.4c01150" target="_blank" >10.1021/acsnano.4c01150</a>
Alternative languages
Result language
angličtina
Original language name
Mechanism of WS<sub>2</sub> Nanotube Formation Revealed by <i>in Situ</i>/<i>ex Situ</i> Imaging
Original language description
Multiwall WS2 nanotubes have been synthesized from W18O49 nanowhiskers in substantial amounts for more than a decade. The established growth model is based on the "surface-inward" mechanism, whereby the high-temperature reaction with H2S starts on the nanowhisker surface, and the oxide-to-sulfide conversion progresses inward until hollow-core multiwall WS2 nanotubes are obtained. In the present work, an upgraded in situ SEM mu Reactor with H-2 and H2S sources has been conceived to study the growth mechanism in detail. A hitherto undescribed growth mechanism, named "receding oxide core", which complements the "surface-inward" model, is observed and kinetically evaluated. Initially, the nanowhisker is passivated by several WS2 layers via the surface-inward reaction. At this point, the diffusion of H2S through the already existing outer layers becomes exceedingly sluggish, and the surface-inward reaction is slowed down appreciably. Subsequently, the tungsten suboxide core is anisotropically volatilized within the core close to its tips. The oxide vapors within the core lead to its partial out-diffusion, partially forming a cavity that expands with reaction time. Additionally, the oxide vapors react with the internalized H2S gas, forming fresh WS2 layers in the cavity of the nascent nanotube. The rate of the receding oxide core mode increases with temperatures above 900 degrees C. The growth of nanotubes in the atmospheric pressure flow reactor is carried out as well, showing that the proposed growth model (receding oxide core) is also relevant under regular reaction parameters. The current study comprehensively explains the WS2 nanotube growth mechanism, combining the known model with contemporary insight.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10403 - Physical chemistry
Result continuities
Project
<a href="/en/project/TN02000020" target="_blank" >TN02000020: Centre of Advanced Electron and Photonic Optics</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2024
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
ACS Nano
ISSN
1936-0851
e-ISSN
1936-086X
Volume of the periodical
18
Issue of the periodical within the volume
19
Country of publishing house
US - UNITED STATES
Number of pages
11
Pages from-to
12284-12294
UT code for WoS article
001225416900001
EID of the result in the Scopus database
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