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Title: Automated processing of environmental transmission electron microscopy images for quantification of thin film dewetting and carbon nanotube nucleation dynamics

Journal Article · · Carbon
 [1];  [1]; ORCiD logo [2];  [3]; ORCiD logo [1]
  1. Massachusetts Institute of Technology (MIT), Cambridge, MA (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Massachusetts Institute of Technology (MIT), Cambridge, MA (United States); Vanderbilt University, Nashville, TN (United States)
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We report scalable production of carbon nanotubes (CNTs) requires catalysts and reaction conditions that provide high nucleation efficiency. In situ characterization methods such as environmental transmission electron microscopy (ETEM) can reveal fundamental mechanisms of synthesis, but to date have primarily provided qualitative observations on small sample sizes. Here, quantitative analysis is performed using high-resolution, high-rate video capture of ETEM experimentation coupled with automated image processing, involving computer vision algorithms and convolutional neural networks. By this approach, we detect distinct nanoparticle formation from an alumina-supported iron thin film and subsequent CNT nucleation from the nanoparticles. The statistical summary of particles in each video shows that, compared to a H2-only atmosphere, pretreatment of the catalyst with carbon added to the H2 atmosphere results in a smaller average particle diameter, a 2-fold increase in particle density (to 5300 particles/μm2), a 3-fold increase in CNT nucleation efficiency (to 92%), and more than a 5-fold increase in CNT density (to 4800/μm2). Addition of carbon during exposure to H2 is also more effective than NH3 at dewetting the catalyst film and increasing the CNT nucleation efficiency, in spite of NH3 being a stronger reducing agent for iron. Insights from this study are applicable to improving CNT yield and productivity in both batch-style and continuous processes.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); National Aeronautics and Space Administration (NASA); MIT Undergraduate Research Opportunities Program (UROP)
Grant/Contract Number:
SC0012704; NNX17AJ32GNASA-USCOMP
OSTI ID:
1888736
Report Number(s):
BNL-223409-2022-JAAM
Journal Information:
Carbon, Vol. 192; ISSN 0008-6223
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (23)

State of Transition Metal Catalysts During Carbon Nanotube Growth journal January 2009
Measurement of the Dewetting, Nucleation, and Deactivation Kinetics of Carbon Nanotube Population Growth by Environmental Transmission Electron Microscopy journal May 2016
Carbon Nanotubes and Related Nanomaterials: Critical Advances and Challenges for Synthesis toward Mainstream Commercial Applications journal November 2018
The Phase of Iron Catalyst Nanoparticles during Carbon Nanotube Growth journal December 2012
Automated defect analysis in electron microscopic images journal July 2018
Mapping mesoscopic phase evolution during E-beam induced transformations via deep learning of atomically resolved images journal June 2018
Isolating the Roles of Hydrogen Exposure and Trace Carbon Contamination on the Formation of Active Catalyst Populations for Carbon Nanotube Growth journal July 2019
Controlling the Morphology of Carbon Nanotube Films by Varying the Areal Density of Catalyst Nanoclusters Using Block-Copolymer Micellar Thin Films journal September 2006
Dense Vertically Aligned Multiwalled Carbon Nanotube Arrays as Thermal Interface Materials journal March 2007
Fast Mass Transport Through Sub-2-Nanometer Carbon Nanotubes journal May 2006
Rapid and Scalable Reduction of Dense Surface-Supported Metal-Oxide Catalyst with Hydrazine Vapor journal June 2009
Deep Learning of Atomically Resolved Scanning Transmission Electron Microscopy Images: Chemical Identification and Tracking Local Transformations journal October 2016
Nitrogen-Mediated Carbon Nanotube Growth: Diameter Reduction, Metallicity, Bundle Dispersability, and Bamboo-like Structure Formation journal November 2007
Carbon-assisted catalyst pretreatment enables straightforward synthesis of high-density carbon nanotube forests journal November 2019
In Situ Study of Iron Catalysts for Carbon Nanotube Growth Using X-Ray Diffraction Analysis journal March 2004
Flexible High-Conductivity Carbon-Nanotube Interconnects Made by Rolling and Printing journal November 2009
84% Catalyst Activity of Water-Assisted Growth of Single Walled Carbon Nanotube Forest Characterization by a Statistical and Macroscopic Approach journal April 2006
Decoupling Catalyst Dewetting, Gas Decomposition, and Surface Reactions in Carbon Nanotube Forest Growth Reveals Dependence of Density on Nucleation Temperature journal November 2019
Direct evidence of active and inactive phases of Fe catalyst nanoparticles for carbon nanotube formation journal November 2014
Nitrogen controlled iron catalyst phase during carbon nanotube growth journal October 2014
Ion exclusion by sub-2-nm carbon nanotube pores journal June 2008
In Situ Observation of the Effect of Nitrogen on Carbon Nanotube Synthesis journal August 2013
Membranes of Vertically Aligned Superlong Carbon Nanotubes journal July 2011

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25 ENERGY STORAGE
carbon nanotubes
ETEM
machine learning
dewetting
image processing