Oxygen adsorption and dissociation during the oxidation of monolayer Ti2C

Gan, Li‐Yong; Huang, Dan; Schwingenschlögl, Udo

doi:10.1039/c3ta12032e

Cited by 84 publications

(72 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…15 Additionally, TiO x adatom complexes are also expected to be mobile on the surface as predicted for other systems. 29 The reduction in edge length of the single sheet is in agreement with minimization of edge energy.…”

mentioning

confidence: 88%

See 1 more Smart Citation

Atomically Resolved Structural and Chemical Investigation of Single MXene Sheets

et al. 2015

View full text Add to dashboard Cite

The properties of two dimensional (2D) materials depend strongly on the chemical and electrochemical activity of their surfaces. MXene, one of the most recent additions to 2D materials, shows great promise as an energy storage material. In the present investigation, the chemical and structural properties of individual Ti 3 C 2 MXene sheets with associated surface groups are investigated at the atomic level by aberration corrected STEM-EELS. The MXene sheets are shown to exhibit a non-uniform coverage of O-based surface groups which locally affect the chemistry. Additionally, native point defects which are proposed to affect the local surface chemistry, such as oxidized titanium adatoms (TiO x ), are identified and found to be mobile. * To whom correspondence should be addressed † Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden The latter originate from the MAX phases, consisting of a transition metal (M), an Agroup (A) element and C or N (X). 4 The significance of the MAX phases stems from their laminated structure, where M n+1 X n sheets are interleaved with atomically thin A layers. 5,6The M-X bonds consist of a mixture of covalent, metallic, and ionic bonds 6 making MXene exceptionally strong and hence appealing for new applications. 6-8MXenes are synthesized from the MAX phases by removal of A-layers through chemical etching, resulting in stand-alone 2D sheets. 5,6,8,9 is crucial to advance the understanding of MXenes. Here, we investigate the structural properties of single, double and multiple sheets of Ti 3 C 2 T x with attached surface groups by atomic-resolution scanning transmission electron microscopy (STEM). The elemental and chemical properties were further investigated by electron energy loss spectroscopy spectrum imaging (EELS SI). Through these methods we identify the atomic structure of the MXene sheets as well as intrinsic defects, surface and edge terminations by the partial coverage of surface groups. We also report on the mobility and migration of intrinsic defects and surface groups.Ti 3 C 2 T x powder was produced from Ti 3 AlC 2 which was prepared by ball-milling Ti 2 AlC (> 92 wt%, 3-ONE-2, Voorhees, NJ) and TiC (99 %, Johnson Matthey Electronic, NY) powders in a 1:1 molar ratio for 24 h using zirconia balls. The mixture was annealed at 1350• C for 2 h in argon. The sintered compact was converted to a powder by milling. Ti 3 C 2 MXene powder was prepared by immersing 2.5 g of < 400 mesh Ti 3 AlC 2 powder in 1 M of NH 4 HF 2 (Sigma Aldrich, USA) solution for 5 days. After treatment the suspension was washed several times using deionized water and centrifuged to separate the settled powder from the supernatant. The settled powders were removed from vials using ethanol and dried at room temperature. TEM samples were prepared by crushing the powder in a mortar and 3 dispersing the powder on a holey carbon Cu TEM-grid, followed by immediately insertion into the TEM.Characterization was performed using the Linköping double corrected FE...

show abstract

mentioning

confidence: 88%

“…16 However, MXene properties can in principle be tuned by surface groups 6,7,[17][18][19] and by native defects. 10 While there have been a number of theoretical investigations on MXenes and their properties, e.g., 7,15 there have been few, if any, direct observations at atomic resolution which [1100]…”

mentioning

confidence: 99%

Atomically Resolved Structural and Chemical Investigation of Single MXene Sheets

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Theoretically, many applications have been proposed for MXenes in electronic [39][40][41][42][43], magnetic [44][45][46][47][48], optical [49,50], thermoelectric [51][52][53][54][55][56], and sensing devices [57], as well as being new potential materials for catalytic and photocatalytic reactions [58][59][60][61][62][63], hydrogen storage media [64,65], and nanoscale superconductivity [66]. Some of MXenes are predicted to be topological insulators with large band gaps involving only d orbitals [67][68][69][70][71].…”

Section: Introductionmentioning

confidence: 99%

Electronic properties and applications of MXenes: a theoretical review

et al. 2017

View full text Add to dashboard Cite

Recent chemical exfoliation of layered MAX phase compounds to novel two-dimensional transition metal carbides and nitrides, so called MXenes, has brought new opportunity to materials science and technology. This review highlights the computational attempts that have been made to understand the physics and chemistry of this very promising family of advanced two-dimensional materials, and to exploit their novel and exceptional properties for electronic and energy harvesting applications.

show abstract

“…24 The second and third order force constants are used for solving a linearised At room temperature the thermal resistivity is dominated by three phonon Umklapp scattering events, whereas scattering events involving four or more phonons become relevant when the temperature exceeds half of the melting temperature. 27 Since molecular dynamics simulations predict that Ti 2 CO 2 remains solid up to 823 K, 28 we limit our analysis to 700 K and consider three phonon scattering events. Hence, for higher temperatures the conductivity values obtained from our procedure constitute upper limits.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Performance of the MXenes M₂CO₂ (M = Ti, Zr, or Hf)

2016

Self Cite

View full text Add to dashboard Cite

We present the first report in which the thermoelectric properties of two-dimensional MXenes are calculated by considering both the electron and phonon transport. Specifically, we solve the transport equations of the electrons and phonons for three MXenes, M 2 CO 2 , where M = Ti, Zr, or Hf, in order to evaluate the effect of the metal M on the thermoelectric performance. The lattice contribution to the thermal conductivity, obtained from the phonon life times, is found to be lowest in Ti 2 CO 2 and highest in Hf 2 CO 2 in the temperature range from 300 K to 700 K. The highest figure of merit is predicted for Ti 2 CO 2 . The heavy mass of the electrons due to flat conduction bands results in a larger thermopower in the case of n-doping in these compounds.

show abstract

Oxygen adsorption and dissociation during the oxidation of monolayer Ti2C

Cited by 84 publications

References 43 publications

Atomically Resolved Structural and Chemical Investigation of Single MXene Sheets

Atomically Resolved Structural and Chemical Investigation of Single MXene Sheets

Electronic properties and applications of MXenes: a theoretical review

Thermoelectric Performance of the MXenes M₂CO₂ (M = Ti, Zr, or Hf)

Contact Info

Product

Resources

About

Oxygen adsorption and dissociation during the oxidation of monolayer Ti2C

Cited by 84 publications

References 43 publications

Atomically Resolved Structural and Chemical Investigation of Single MXene Sheets

Atomically Resolved Structural and Chemical Investigation of Single MXene Sheets

Electronic properties and applications of MXenes: a theoretical review

Thermoelectric Performance of the MXenes M2CO2 (M = Ti, Zr, or Hf)

Contact Info

Product

Resources

About

Thermoelectric Performance of the MXenes M₂CO₂ (M = Ti, Zr, or Hf)