Two-dimensional transition-metal carbides and nitrides (MXenes) are a large family of materials actively studied for various applications, especially in the field of energy storage. MXenes are commonly synthesized by etching the layered ternary compounds, called MAX phases. We demonstrate a direct synthetic route for scalable and atom-economic synthesis of MXenes, including compounds that have not been synthesized from MAX phases, by the reactions of metals and metal halides with graphite, methane, or nitrogen. The direct synthesis enables chemical vapor deposition growth of MXene carpets and complex spherulite-like morphologies that form through buckling and release of MXene carpet to expose fresh surface for further reaction. The directly synthesized MXenes showed excellent energy storage capacity for lithium-ion intercalation.
Journal Article Crystal Surfaces and Their Role on Electrochemical Activity in MgV2O4 Crystals Get access Francisco J Lagunas Vargas, Francisco J Lagunas Vargas Joint Center for Energy Storage Research, Argonne National Laboratory, Lemont, Illinois, United StatesDepartment of Physics, University of Illinois at Chicago, Chicago, Illinois, United States Corresponding author: flagun2@uic.edu Search for other works by this author on: Oxford Academic Google Scholar Grant C B Alexander, Grant C B Alexander Joint Center for Energy Storage Research, Argonne National Laboratory, Lemont, Illinois, United StatesDepartment of Chemistry, University of Illinois at Chicago, Chicago, Illinois, United States Search for other works by this author on: Oxford Academic Google Scholar Adriana Lee Punaro, Adriana Lee Punaro Department of Chemistry and Nanotechnology, Tecnologico de Monterrey, Monterrey, Mexico Search for other works by this author on: Oxford Academic Google Scholar Christian Moscosa, Christian Moscosa Joint Center for Energy Storage Research, Argonne National Laboratory, Lemont, Illinois, United StatesDepartment of Chemistry, University of Illinois at Chicago, Chicago, Illinois, United States Search for other works by this author on: Oxford Academic Google Scholar Jordi Cabana, Jordi Cabana Joint Center for Energy Storage Research, Argonne National Laboratory, Lemont, Illinois, United StatesDepartment of Chemistry, University of Illinois at Chicago, Chicago, Illinois, United States Search for other works by this author on: Oxford Academic Google Scholar Robert F Klie Robert F Klie Joint Center for Energy Storage Research, Argonne National Laboratory, Lemont, Illinois, United StatesDepartment of Physics, University of Illinois at Chicago, Chicago, Illinois, United States Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 28, Issue S1, 1 August 2022, Pages 2604–2605, https://doi.org/10.1017/S1431927622009898 Published: 01 August 2022
Journal Article Characterizing TeO2 Formation in CdTe Devices Using Transmission Electron Microscopy Get access John Farrell, John Farrell University of Illinois at Chicago, Chicago, IL, United States Corresponding author: jjfarre2@uic.edu Search for other works by this author on: Oxford Academic Google Scholar Ebin Bastola, Ebin Bastola University of Toledo, Toledo, OH, United States Search for other works by this author on: Oxford Academic Google Scholar Manoj Jamarkattel, Manoj Jamarkattel University of Toledo, Toledo, OH, United States Search for other works by this author on: Oxford Academic Google Scholar Michael Heben, Michael Heben University of Toledo, Toledo, OH, United States Search for other works by this author on: Oxford Academic Google Scholar Walajabad S Sampath, Walajabad S Sampath Colorado State University, Fort Collins, CO, United States Search for other works by this author on: Oxford Academic Google Scholar James Sites, James Sites Colorado State University, Fort Collins, CO, United States Search for other works by this author on: Oxford Academic Google Scholar Robert F Klie Robert F Klie University of Illinois at Chicago, Chicago, IL, United States Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Pages 1661–1662, https://doi.org/10.1093/micmic/ozad067.855 Published: 22 July 2023
A multitude of characterization techniques that can be applied across a wide range of length scales and to a variety of materials are available on modern scanning transmission electron microscopes (STEM). In 2011, such an instrument was installed at the University of Illinois at Chicago: the aberration‐corrected cold‐field emission JEOL JEM‐ARM200CF, capable of atomic‐resolution imaging and spectroscopy in a temperature range between 80–1300 K. This paper will review a number of studies focusing on both structural and chemical characterization of materials including NbH, SrTiO 3 , Pt catalysts and Al x Ga 1– x N nanowires. Microscope versatility, a central theme of this work, is realized through the ability to perform fine‐scale chemical characterization while retaining high spatial resolution. Of particular interest to many studies is the visualization of light elements, such as N, O or H, using simultaneous high‐angle annular dark‐field (HAADF) and annular bright‐field (ABF) imaging.
Abstract The heterogeneous catalytic system Pt/SiO2 is widely used in “three-way” catalysts, because of its highly selective catalytic reduction of NO by hydrocarbons at low operating temperatures. Although used effectively for more than a decade, in recent years it has become clear that the core phenomena of heterogeneous catalysis can occur at interfaces. in the work presented here, we seek to better understand the role of the atomic and electronic structure of interfaces in making particular reactions facile and moderating the stability and selectivity of a catalytic system. We investigate model supported platinum catalysts by atomic resolution Z-contrast imaging and EELS using a 200 kV STEM/TEM JEOL2010F with a post column GIF. The combination of these techniques allows us to obtain direct images of the metal particle and its interface with the supporting SiO2, and to correlate that with the modulation of the Si L-edge fine structure.
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