title: Two-Dimensional, Ordered, Double Transition Metals Carbides (MXenes).
abstract: The higher the chemical diversity and structural complexity of two-dimensional (2D) materials, the higher the likelihood they possess unique and useful properties. Herein, density functional theory (DFT) is used to predict the existence of two new families of 2D ordered, carbides (MXenes), M'2M″C2 and M'2M″2C3, where M' and M″ are two different early transition metals. In these solids, M' layers sandwich M″ carbide layers. By synthesizing Mo2TiC2Tx, Mo2Ti2C3Tx, and Cr2TiC2Tx (where T is a surface termination), we validated the DFT predictions. Since the Mo and Cr atoms are on the outside, they control the 2D flakes' chemical and electrochemical properties. The latter was proven by showing quite different electrochemical behavior of Mo2TiC2Tx and Ti3C2Tx. This work further expands the family of 2D materials, offering additional choices of structures, chemistries, and ultimately useful properties.
authors.affiliation: Department of Materials Science & Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.|A.J. Drexel Nanomaterials Institute, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Babak
authors.initials: B
authors.lastname: Anasori
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37381, United States.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Materials Science & Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.|A.J. Drexel Nanomaterials Institute, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Majid
authors.initials: M
authors.lastname: Beidaghi
authors.affiliation: Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University , SE-581 83 Linköping, Sweden.
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Materials Science & Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Hosler
authors.affiliation: Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University , SE-581 83 Linköping, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Hultman
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37381, United States.|Computer Science and Mathematics Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37381, United States.
authors.forename: Paul R C
authors.initials: PR
authors.lastname: Kent
authors.affiliation: Department of Materials Science & Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.|A.J. Drexel Nanomaterials Institute, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Yury
authors.initials: Y
authors.lastname: Gogotsi
authors.affiliation: Department of Materials Science & Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Michel W
authors.initials: MW
authors.lastname: Barsoum
keywords: 2D materials; DFT calculations; MXene; electrochemical properties