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Title: In situ Environmental Transmission Electron Microscopy Study of Oxidation of Two-Dimensional Ti3C2 and Formation of Carbon-Supported TiO2

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC); Fluid Interface Reactions, Structures and Transport Center (FIRST)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1167945
DOE Contract Number:
ERKCC61
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Mater. Chem. A; Journal Volume: 2; Related Information: FIRST partners with Oak Ridge National Laboratory (lead); Argonne National Laboratory; Drexel University; Georgia State University; Northwestern University; Pennsylvania State University; Suffolk University; Vanderbilt University; University of Virginia
Country of Publication:
United States
Language:
English
Subject:
catalysis (heterogeneous), solar (fuels), energy storage (including batteries and capacitors), hydrogen and fuel cells, electrodes - solar, mechanical behavior, charge transport, materials and chemistry by design, synthesis (novel materials)

Citation Formats

Ghassemi, H., Harlow, W., Mashtalir, Olha, Beidaghi, M., Lukatskaya, M., Gogotsi, Y., and Taheri, Mitra L. In situ Environmental Transmission Electron Microscopy Study of Oxidation of Two-Dimensional Ti3C2 and Formation of Carbon-Supported TiO2. United States: N. p., 2014. Web. doi:10.1039/c4ta02583k.
Ghassemi, H., Harlow, W., Mashtalir, Olha, Beidaghi, M., Lukatskaya, M., Gogotsi, Y., & Taheri, Mitra L. In situ Environmental Transmission Electron Microscopy Study of Oxidation of Two-Dimensional Ti3C2 and Formation of Carbon-Supported TiO2. United States. doi:10.1039/c4ta02583k.
Ghassemi, H., Harlow, W., Mashtalir, Olha, Beidaghi, M., Lukatskaya, M., Gogotsi, Y., and Taheri, Mitra L. Tue . "In situ Environmental Transmission Electron Microscopy Study of Oxidation of Two-Dimensional Ti3C2 and Formation of Carbon-Supported TiO2". United States. doi:10.1039/c4ta02583k.
@article{osti_1167945,
title = {In situ Environmental Transmission Electron Microscopy Study of Oxidation of Two-Dimensional Ti3C2 and Formation of Carbon-Supported TiO2},
author = {Ghassemi, H. and Harlow, W. and Mashtalir, Olha and Beidaghi, M. and Lukatskaya, M. and Gogotsi, Y. and Taheri, Mitra L.},
abstractNote = {},
doi = {10.1039/c4ta02583k},
journal = {J. Mater. Chem. A},
number = ,
volume = 2,
place = {United States},
year = {Tue Jul 08 00:00:00 EDT 2014},
month = {Tue Jul 08 00:00:00 EDT 2014}
}
  • Two-dimensional Ti3C2, also known as “MXene”, was oxidized in air under two different oxidizing regimes in order to produce carbon-supported TiO2. In situ TEM analysis coupled with Raman spectroscopy revealed the formation of either anatase nanoparticles or planar rutile nanocrystals, which were controlled by the time, temperature and heating rate.
  • We oxidized two-dimensional Ti 3C 2, also known as “MXene” in air under two different oxidizing regimes in order to produce carbon-supported TiO 2. Furthermore, the in situ TEM analysis coupled with Raman spectroscopy revealed the formation of either anatase nanoparticles or planar rutile nanocrystals, which were controlled by the time, temperature and heating rate.
  • Palladium clusters, 10-30 nm in size, were grown in UHV on amorphous carbon in a transmission electron microscope (TEM). The Pd catalyzed oxidation of carbon was then followed in situ in the TEM between 720 and 800 K at a pressure p of O[sub 2] with 0.25 < p (10[sup [minus]4] mbar) < 1.0. The behavior of hundreds of individual clusters was recorded on videotape in real time. Clusters moved as they dug irregular channels throughout the carbon film. They exhibited liquid-like behavior and frequent change of contrast (flashing). These active clusters started to move after an induction period. Somemore » clusters remained inactive. Active clusters coalesced with inactive clusters to form active clusters. After some time, active clusters became and remained inactive. The site time yield of catalyzed oxidation, defined as the number of C atoms reacting per exposed Pd atom per second was almost independent of temperature and proportional to pressure of O[sub 2]. Under the conditions of this work, it appears that the rate determining step of the oxidation of carbons is the dissociative chemisorption of O[sub 2] on Pd, with every O[sub 2] molecule sticking to the Pd surface reacting to C with formation of CO[sub 2].« less
  • In this Environmental TEM (ETEM) study of supported Pt and Pd model catalysts, individual nanoparticles were tracked during heat treatments at temperatures up to 600°C in H2, O2, and vacuum. We found anomalous growth of nanoparticles occurred during the early stages of catalyst sintering wherein some particles started to grow significantly larger than the mean, resulting in a broadening of the particle size distribution. We can rule out sample non-uniformity as a cause for the growth of these large particles, since images were recorded prior to heat treatments. The anomalous growth of these particles may help explain particle size distributionsmore » in heterogeneous catalysts which often show particles that are significantly larger than the mean, resulting in a long tail to the right. It has been suggested that particle migration and coalescence could be the likely cause for the broad size distributions. This study shows that anomalous growth of nanoparticles can occur under conditions where Ostwald ripening is the primary sintering mechanism.« less
  • The early-stage oxidation of Ni (001) thin films alloyed with 10 or 20 at% Cr at 700 °C has been directly visualized using environmental transmission electron microscopy. Independent of Cr concentration, the oxidation initiates via the nucleation of surface NiO islands and subsurface Cr2O3. The NiO grows and transitions into a continuous film, followed by the nucleation and growth of NiCr2O4 islands through the outer oxide. The Cr concentration plays a more critical role in the later stages of the oxidation. A continuous and more protective Cr2O3 sublayer is established for Ni-20at% Cr, while the Cr2O3 sublayer for Ni-10at%Cr ismore » discontinuous for Ni-10at%Cr. Oxidation persists on the lower Cr alloy where NiO whiskers are observed to preferentially nucleate and grow from the NiCr2O4 islands. It is suggested that short-circuit diffusion of Ni occurs along the NiCr2O4 interfaces through the discontinuous Cr2O3 layer in Ni-10at%Cr to facilitate the selective nucleation of NiO whiskers on the NiCr2O4 surfaces. Conversely, the protective nature of the continuous Cr2O3 film in Ni-20at%Cr blocks this short-circuit pathway and prevents the formation of additional NiO on the surface in the early stage oxidation.« less