An X-Ray Photoelectron Spectroscopy Study of Multilayered Transition Metal Carbides (MXenes)

2021 ◽  
Author(s):  
Joseph Halim
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Spectroscopy Study ◽  
Metal Carbides ◽  
X Ray ◽  
Transition Metal Carbides

scholarly journals X-ray photoelectron spectroscopy of select multi-layered transition metal carbides (MXenes)

2016 ◽  
Vol 362 ◽  
pp. 406-417 ◽  
Author(s):  
Joseph Halim ◽  
Kevin M. Cook ◽  
Michael Naguib ◽  
Per Eklund ◽  
Yury Gogotsi ◽  
...  
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Metal Carbides ◽  
X Ray ◽  
Transition Metal Carbides ◽  
Layered Transition Metal

scholarly journals The Temperature Factor Parameters of Some Transition Metal Carbides and Nitrides by Single Crystal X-Ray and Neutron Diffraction.

1978 ◽  
Vol 32a ◽  
pp. 89-90 ◽  
Author(s):  
A. Nørlund Christensen ◽  
Reijo Hämäläinen ◽  
Urho Turpeinen ◽  
Arne F. Andresen ◽  
Olav Smidsrød ◽  
...  
Keyword(s):  
Transition Metal ◽  
Neutron Diffraction ◽  
Single Crystal ◽  
Temperature Factor ◽  
Metal Carbides ◽  
X Ray ◽  
Transition Metal Carbides

scholarly journals XPS of Cold Pressed Multilayered and Freestanding Delaminated 2D Thin Films of Mo2TiC2Tz and Mo2Ti2C3Tz (MXenes)

2019 ◽  
Author(s):  
Joseph Halim ◽  
Kevin Cook ◽  
Per Eklund ◽  
johanna Rosen ◽  
Michel W. Barsoum
Keyword(s):  
Photoelectron Spectroscopy ◽  
Formula Unit ◽  
Metal Carbides ◽  
Max Phases ◽  
X Ray ◽  
Transition Metal Carbides ◽  
Out Of Plane ◽  
Xps Study ◽  
Cold Pressed ◽  
Harsh Conditions

<p>MXenes, transition metal carbides that are synthesized from the top down by etching of their 3D parent layered solids, the MAX phases, are the latest family of the two-dimensional solids discovered. When the A layers – mostly Al – are etched they are replaced by surface terminations, T<sub>z</sub> mainly comprised of O-, OH- and F-terminations. One of the few techniques capable of quantifying these surface terminations is X-ray photoelectron spectroscopy, XPS. Herein, we undertook an XPS study of the out-of-plane ordered MXenes, Mo<sub>2</sub>TiC<sub>2</sub>T<sub>z</sub> and Mo<sub>2</sub>Ti<sub>2</sub>C<sub>3</sub>T<sub>z</sub>, in both multilayered, ML, cold pressed and delaminated thin film forms. The harsh conditions needed to etch these MAX phases into MLs, results in their partial oxidation. The hydroxide used to delaminate the MLs results in further oxidation and a reduction in the F-content. In all cases, etching resulted in a decrease in the Ti to Mo ratio implying that the former atoms are selectively etched. In all but the ML Mo<sub>2</sub>TiC<sub>2</sub>T<sub>z</sub> case, the Mo to C ratio was also reduced. It follows that the loss of Ti also results in the loss of C atoms. With the exception of the ML Mo<sub>2</sub>Ti<sub>2</sub>C<sub>3</sub>T<sub>z</sub> case, the number of termination moles per formula unit, z, was > 2, which is energetically unfavorable and thus unlikely. However, if one assumes that not all of the O signal is coming from terminations but rather from O atoms that replace C atoms in the MX blocks, then z ≈ 2. This work is an important step in quantifying and understanding the effects of etching on terminations and structure in these Mo and Ti-based MXenes. </p>

scholarly journals Electrochemical Passivation Properties of Valve Transition Metal Carbides

2022 ◽  
Author(s):  
Daniel Goehl ◽  
Holger Rueß ◽  
Andrea M Mingers ◽  
Karl Johann Jakob Mayrhofer ◽  
Jochen M Schneider ◽  
...  
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Polymer Electrolyte Membrane ◽  
Catalyst Support ◽  
Tantalum Carbide ◽  
Metal Carbides ◽  
Support Materials ◽  
Transition Metal Carbides ◽  
Electrochemical Passivation

Abstract Transition metal carbides have the potential to be employed as corrosion protective coating for a variety of applications such as e.g. steel based bipolar plates, porous transport layers or as catalyst support in polymer electrolyte membrane fuel cells and water electrolyzers. Yet, little is known of their fundamental, intrinsic corrosion and passivation properties. Herein, we conducted a detailed electrochemical passivation study of various valve transition metal carbides such as titanium carbide, tantalum carbide or tungsten carbide. Via flow cell measurements coupled to an inductively coupled plasma mass spectrometer, the in-situ transition metal dissolution was monitored, and the faradaic dissolution efficiency was calculated. Together with the determination of the grown oxide layer via X-ray photoelectron spectroscopy, a thorough evaluation of the passivation efficiency was conducted. Moreover, it was shown that a beneficial stabilization effect can be achieved through alloying of different carbides, which paves the way towards tailor-made coatings or catalyst support materials.

scholarly journals XPS of Cold Pressed Multilayered and Freestanding Delaminated 2D Thin Films of Mo2TiC2Tz and Mo2Ti2C3Tz (MXenes)

2019 ◽  
Author(s):  
Joseph Halim ◽  
Kevin Cook ◽  
Per Eklund ◽  
johanna Rosen ◽  
Michel W. Barsoum
Keyword(s):  
Photoelectron Spectroscopy ◽  
Formula Unit ◽  
Metal Carbides ◽  
Max Phases ◽  
X Ray ◽  
Transition Metal Carbides ◽  
Out Of Plane ◽  
Xps Study ◽  
Cold Pressed ◽  
Harsh Conditions

<p>MXenes, transition metal carbides that are synthesized from the top down by etching of their 3D parent layered solids, the MAX phases, are the latest family of the two-dimensional solids discovered. When the A layers – mostly Al – are etched they are replaced by surface terminations, T<sub>z</sub> mainly comprised of O-, OH- and F-terminations. One of the few techniques capable of quantifying these surface terminations is X-ray photoelectron spectroscopy, XPS. Herein, we undertook an XPS study of the out-of-plane ordered MXenes, Mo<sub>2</sub>TiC<sub>2</sub>T<sub>z</sub> and Mo<sub>2</sub>Ti<sub>2</sub>C<sub>3</sub>T<sub>z</sub>, in both multilayered, ML, cold pressed and delaminated thin film forms. The harsh conditions needed to etch these MAX phases into MLs, results in their partial oxidation. The hydroxide used to delaminate the MLs results in further oxidation and a reduction in the F-content. In all cases, etching resulted in a decrease in the Ti to Mo ratio implying that the former atoms are selectively etched. In all but the ML Mo<sub>2</sub>TiC<sub>2</sub>T<sub>z</sub> case, the Mo to C ratio was also reduced. It follows that the loss of Ti also results in the loss of C atoms. With the exception of the ML Mo<sub>2</sub>Ti<sub>2</sub>C<sub>3</sub>T<sub>z</sub> case, the number of termination moles per formula unit, z, was > 2, which is energetically unfavorable and thus unlikely. However, if one assumes that not all of the O signal is coming from terminations but rather from O atoms that replace C atoms in the MX blocks, then z ≈ 2. This work is an important step in quantifying and understanding the effects of etching on terminations and structure in these Mo and Ti-based MXenes. </p>

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