Abstract
Control of surface functionalization of MXenes holds great potential, and in particular, may lead to tuning of magnetic and electronic order in the recently reported magnetic Cr2TiC2Tx. Here, vacuum annealing experiments of Cr2TiC2Tx are reported with in situ electron energy loss spectroscopy and novel in situ Cr K-edge extended energy loss fine structure analysis, which directly tracks the evolution of the MXene surface coordination environment. These in situ probes are accompanied by benchmarking synchrotron X-ray absorption fine structure measurements and density functional theory calculations. With the etching method used here, the MXene has an initial termination chemistry of Cr2TiC2O1.3F0.8. Annealing to 600 °C results in the complete loss of -F, but -O termination is thermally stable up to (at least) 700 °C. These findings demonstrate thermal control of F termination in Cr2TiC2Tx and offer a first step toward termination engineering this MXene for magnetic applications. Moreover, this work demonstrates high energy electron spectroscopy as a powerful approach for surface characterization in 2D materials.
Original language | English |
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Article number | 2001789 |
Journal | Advanced Materials Interfaces |
Volume | 8 |
Issue number | 5 |
DOIs | |
State | Published - Mar 9 2021 |
Externally published | Yes |
Funding
J.L.H., A.C.L., and M.L.T. acknowledge funding from the National Science Foundation (NSF) MRI Award #DMR‐1429661. Y.L. and A.I.F. acknowledge support from the NSF Award #DMR‐1911592 for the XAFS measurements and XAFS and EXELFS data analyses. K.H. and Y.G. acknowledge financial support from the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Grant No. DE‐SC0018618. The Cr K‐edge XAFS data were acquired at beamline 7‐BM (QAS) of the National Synchrotron Light Source II (NSLS‐II), a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory (BNL) under Contract No. DE‐ SC0012704. Prof. Babak Anasori is acknowledged for providing CrTiAlC MAX phase used in this study. 2 2 J.L.H., A.C.L., and M.L.T. acknowledge funding from the National Science Foundation (NSF) MRI Award #DMR-1429661. Y.L. and A.I.F. acknowledge support from the NSF Award #DMR-1911592 for the XAFS measurements and XAFS and EXELFS data analyses. K.H. and Y.G. acknowledge financial support from the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Grant No. DE-SC0018618. The Cr K-edge XAFS data were acquired at beamline 7-BM (QAS) of the National Synchrotron Light Source II (NSLS-II), a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory (BNL) under Contract No. DE- SC0012704. Prof. Babak Anasori is acknowledged for providing Cr2TiAlC2 MAX phase used in this study.
Keywords
- 2D materials
- MXenes
- electron energy loss spectroscopy
- in situ characterization
- surface chemistry