| AVS 63rd International Symposium & Exhibition | |
| 2D Materials Focus Topic | Tuesday Sessions |
| Session 2D+MI-TuM |
| Session: | Novel 2D Materials |
| Presenter: | Chung-Chuan Lai, Linköping University, Sweden |
| Authors: | C.-C. Lai, Linköping University, Sweden R. Meshkian, Linköping University, Sweden M. Dahlqvist, Linköping University, Sweden J. Lu, Linköping University, Sweden L.-Å. Näslund, Linköping University, Sweden O. Rivin, Nuclear Research Center-Negev, Israel E.N. Caspi, Nuclear Research Center-Negev, Israel O. Ozeri, Nuclear Research Center-Soreq, Israel L. Hultman, Linköping University, Sweden P. Eklund, Linköping University, Sweden M.W. Barsoum, Drexel University J. Rosen, Linköping University, Sweden |
| Correspondent: | Click to Email |
Studies of molybdenum carbides are motivated by, for example, the electric and the catalysis properties, including the recently predicted high Seebeck coefficient of 2D Mo2C [1]. It has been reported that 2D transition metal carbides (also known as MXenes) can be made by selective etching of corresponding nanolaminated ternary carbides [2], e.g., Mn+1ACn phases where M is typically from group 4 – 6, A is from group 13 – 14, and n is 1 – 4 [3]. However, no suitable precursor has been available to make 2D Mo2C until most recently, through the discovery of Mo2Ga2C [4]. Here, we determined the structure of Mo2Ga2C phase from X-ray and neutron diffraction, scanning transmission electron microscopy and X-ray photoelectron spectroscopy, and further validated the structure by ab initio calculations [5]. The structure of Mo2Ga2C can be described as Mo2C layers interleaved by two Ga layers, standing head-to-head along the c-axis of the hexagonal lattice. The Mo2Ga2C phase is closely related to another known nanolaminated carbide, Mo2GaC, in its crystal structures, evident from chemical bonding analysis. However, selective etching of Ga using hydrofluoric acid (HF) is easily attained for the new Mo2Ga2C phase, while being more challenging for Mo2GaC. A reduction in Ga signal with subsequent exfoliation of Mo2C layers upon etching is here presented for Mo2Ga2C, making Mo2Ga2C the first precursor for MXene synthesis based on A = Ga, and for MXene synthesis of 2D Mo2C [6].
References:
[1] M. Khazaei, M. Arai, T. Sasaki, M. Estili, and Y. Sakka, Phys. Chem. Chem. Phys. 16 (2014) 7841-7849.
[2] M. Naguib, G. W. Bentzel, J. Shah, J. Halim, E. N. Caspi, J. Lu, L. Hultman, and M. W. Barsoum, Mater. Res. Lett. 2 (2014) 233-240.
[3] P. Eklund, M. Beckers, U. Jansson, H. Högberg, and L. Hultman, Thin Solid Films 518 (2010) 1851-1878.
[4] C. Hu, C.-C. Lai, Q. Tao, J. Lu, J. Halim, L. Sun, J. Zhang, J. Yang, B. Anasori, J. Wang, Y. Sakka, L. Hultman, P. Eklund, J. Rosen, and M. W. Barsoum, Chem. Commun. 51 (2015) 6560.
[5] C.-C. Lai, R. Meshkian, M. Dahlqvist, J. Lu, L.-Å. Näslund, O. Rivin, E. N. Caspi, O. Ozeri, L. Hultman, P. Eklund, M. W. Barsoum, and J. Rosen, Acta Mater. 99 (2015) 157-164.
[6] R. Meshkian, L.-Å. Näslund, J. Halim, J. Lu, M. W. Barsoum, and J. Rosen, Scripta Mater. 108 (2015) 147-150.