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Sharma S, Pasricha R, Weston J, Blanton T, Jagannathan R. Synthesis of Self-Assembled Single Atomic Layer Gold Crystals-Goldene. ACS APPLIED MATERIALS & INTERFACES 2022; 14:54992-55003. [PMID: 36453468 PMCID: PMC9756290 DOI: 10.1021/acsami.2c19743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 11/18/2022] [Indexed: 06/17/2023]
Abstract
We report, for the first time, a technique to synthesize free-standing, one-atom thick 2D gold crystals (namely, goldene) and self-assembled 2D periodic arrays of goldene. High-resolution transmission electron microscopy (HRTEM) imaging of goldene revealed herringbone and honeycomb lattices, which are primarily gold surface features due to its reconstruction. Imaging of these surface-only features by a nonsurface characterization technique such as HRTEM is an unequivocal proof of the absence of three-dimensionality in goldene. Atomic force microscopy confirmed 1-2 Å thickness of goldene. High-resolution X-ray photoelectron spectroscopy (HR-XPS), selective area electron diffraction, and energy-dispersive X-ray spectroscopy confirmed the chemical identity of goldene. We discovered the phenomenon of electric field-induced self-assembly of goldene supracrystals with a herringbone structure and developed an electric field printing (e-print) technique for goldene arrays. Goldene showed a semiconductor response with a knee voltage of ∼3.2 V, and I/V spectroscopy revealed periodic room temperature Coulomb blockade oscillations. These observations are consistent with the theoretical calculations reported in the literature predicting enhanced Coulombic interactions between gold valence electrons and the nucleus in stable 2D gold. Goldene exhibited multiple, intense, and well-resolved optical absorption peaks and several fine bands across the UV-vis region, and we calculated its optical band gap to be 3.59 eV. Magnetic force microscopy measurements of goldene periodic arrays showed a ∼5 mV peak amplitude confirming its ferromagnetism. Optical and magnetic properties of goldene are consistent with those reported in the literature for 2D planar gold clusters with less than 12 atoms.
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Affiliation(s)
- Sudhir
Kumar Sharma
- Engineering
Division, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
| | - Renu Pasricha
- Core
Technology Platform, New York University
Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
| | - James Weston
- Core
Technology Platform, New York University
Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
| | - Thomas Blanton
- International
Centre for Diffraction Data, 12 Campus Boulevard, Newtown
Square, Pennsylvania 19073, United States
| | - Ramesh Jagannathan
- Engineering
Division, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
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Ranjan P, Saptal VB, Bera JK. Recent Advances in Carbon Dioxide Adsorption, Activation and Hydrogenation to Methanol using Transition Metal Carbides. CHEMSUSCHEM 2022; 15:e202201183. [PMID: 36036640 DOI: 10.1002/cssc.202201183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/29/2022] [Indexed: 06/15/2023]
Abstract
The inevitable emission of carbon dioxide (CO2 ) due to the burning of a substantial amount of fossil fuels has led to serious energy and environmental challenges. Metal-based catalytic CO2 transformations into commodity chemicals are a favorable approach in the CO2 mitigation strategy. Among these transformations, selective hydrogenation of CO2 to methanol is the most promising process that not only fulfils the energy demands but also re-balances the carbon cycle. The investigation of CO2 adsorption on the surface of heterogeneous catalyst is highly important because the formation of various intermediates which determines the selectivity of product. Transition metal carbides (TMCs) have received considerable attention in recent years because of their noble metal-like reactivity, ceramic-like properties, high chemical and thermal stability. These features make them excellent catalytic materials for a variety of transformations such as CO2 adsorption and its conversion into value-added chemicals. Herein, the catalytic properties of TMCs are summarize along with synthetic methods, CO2 binding modes, mechanistic studies, effects of dopant on CO2 adsorption, and carbon/metal ratio in the CO2 hydrogenation reaction to methanol using computational as well as experimental studies. Additionally, this Review provides an outline of the challenges and opportunities for the development of potential TMCs in CO2 hydrogenation reactions.
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Affiliation(s)
- Prabodh Ranjan
- Department of Chemistry and Center for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Vitthal B Saptal
- Department of Chemistry and Center for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Jitendra K Bera
- Department of Chemistry and Center for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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Gold Carbide: A Predicted Nanotube Candidate from First Principle. NANOMATERIALS 2021; 11:nano11123182. [PMID: 34947530 PMCID: PMC8708319 DOI: 10.3390/nano11123182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/19/2021] [Accepted: 11/20/2021] [Indexed: 11/16/2022]
Abstract
In the present work, density functional theory (DFT) calculations were applied to confirm that the gold carbide previously experimentally synthesized was AuC film. A crucial finding is that these kinds of AuC films are self-folded on the graphite substrate, leading to the formation of a semi-nanotube structure, which significantly diminishes the error between the experimental and simulated lattice constant. The unique characteristic, the spontaneous archlike reconstruction, makes AuC a possible candidate for self-assembled nanotubes. The band structure indicated, in the designed AuC nanotube, a narrow gap semiconductor with a bandgap of 0.14 eV. Both AIMD (at 300 and 450 K) results and phonon spectra showed a rather high stability for the AuC nanotube because a strong chemical bond formed between the Au–5d and C–2p states. The AuC nanotube could become a novel functional material.
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Tieu P, Yan X, Xu M, Christopher P, Pan X. Directly Probing the Local Coordination, Charge State, and Stability of Single Atom Catalysts by Advanced Electron Microscopy: A Review. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2006482. [PMID: 33624398 DOI: 10.1002/smll.202006482] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/18/2020] [Indexed: 06/12/2023]
Abstract
The drive for atom efficient catalysts with carefully controlled properties has motivated the development of single atom catalysts (SACs), aided by a variety of synthetic methods, characterization techniques, and computational modeling. The distinct capabilities of SACs for oxidation, hydrogenation, and electrocatalytic reactions have led to the optimization of activity and selectivity through composition variation. However, characterization methods such as infrared and X-ray spectroscopy are incapable of direct observations at atomic scale. Advances in transmission electron microscopy (TEM) including aberration correction, monochromators, environmental TEM, and micro-electro-mechanical system based in situ holders have improved catalysis study, allowing researchers to peer into regimes previously unavailable, observing critical structural and chemical information at atomic scale. This review presents recent development and applications of TEM techniques to garner information about the location, bonding characteristics, homogeneity, and stability of SACs. Aberration corrected TEM imaging routinely achieves sub-Ångstrom resolution to reveal the atomic structure of materials. TEM spectroscopy provides complementary information about local composition, chemical bonding, electronic properties, and atomic/molecular vibration with superior spatial resolution. In situ/operando TEM directly observe the evolution of SACs under reaction conditions. This review concludes with remarks on the challenges and opportunities for further development of TEM to study SACs.
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Affiliation(s)
- Peter Tieu
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | - Xingxu Yan
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
| | - Mingjie Xu
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
- Irvine Materials Research Institute (IMRI), University of California, Irvine, CA, 92697, USA
| | - Phillip Christopher
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
- Irvine Materials Research Institute (IMRI), University of California, Irvine, CA, 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA
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Joseph T, Ghorbani-Asl M, Kvashnin AG, Larionov KV, Popov ZI, Sorokin PB, Krasheninnikov AV. Nonstoichiometric Phases of Two-Dimensional Transition-Metal Dichalcogenides: From Chalcogen Vacancies to Pure Metal Membranes. J Phys Chem Lett 2019; 10:6492-6498. [PMID: 31589053 DOI: 10.1021/acs.jpclett.9b02529] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Two-dimensional (2D) membranes consisting of a single layer of Mo atoms were recently manufactured [ Adv. Mater. 2018 , 30 , 1707281 ] from MoSe2 sheets by sputtering Se atoms using an electron beam in a transmission electron microscope. This is an unexpected result as formation of Mo clusters should energetically be more favorable. To get microscopic insights into the energetics of realistic Mo membranes and nonstoichiometric phases of transition-metal dichalcogenides (TMDs) MaXb, where M = Mo and W and X = S, Se, and Te, we carry out first-principles calculations and demonstrate that the membranes, which can be referred to as metallic quantum dots embedded into a semiconducting matrix, can be stabilized by charge transfer. We also show that an ideal neutral 2D Mo or W sheet is not flat but a corrugated structure, with a square lattice being the lowest-energy configuration. We further demonstrate that several intermediate nonstoichiometric phases of TMDs are possible as they have lower formation energies than pure metal membranes. Among them, the orthorhombic metallic 2D M4X4 phase is particularly stable. Finally, we study the properties of this phase in detail and discuss how it can be manufactured by the top-down approaches.
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Affiliation(s)
- T Joseph
- Institute of Ion Beam Physics and Materials Research , Helmholtz-Zentrum Dresden-Rossendorf , 01328 Dresden , Germany
| | - M Ghorbani-Asl
- Institute of Ion Beam Physics and Materials Research , Helmholtz-Zentrum Dresden-Rossendorf , 01328 Dresden , Germany
| | - A G Kvashnin
- Skolkovo Institute of Science and Technology , Skolkovo Innovation Center , 3 Nobel Street , Moscow 121205 , Russia
| | - K V Larionov
- National University of Science and Technology "MISIS" , Leninsky prospect 4 , Moscow 119049 , Russia
- Moscow Institute of Physics and Technology , Institutsky lane 9 , Dolgoprudny , Moscow region , 141700 , Russian Federation
| | - Z I Popov
- National University of Science and Technology "MISIS" , Leninsky prospect 4 , Moscow 119049 , Russia
- Emanuel Institute of Biochemical Physics RAS , Moscow 119334 , Russia
| | - P B Sorokin
- National University of Science and Technology "MISIS" , Leninsky prospect 4 , Moscow 119049 , Russia
- Moscow Institute of Physics and Technology , Institutsky lane 9 , Dolgoprudny , Moscow region , 141700 , Russian Federation
- Emanuel Institute of Biochemical Physics RAS , Moscow 119334 , Russia
| | - Arkady V Krasheninnikov
- Institute of Ion Beam Physics and Materials Research , Helmholtz-Zentrum Dresden-Rossendorf , 01328 Dresden , Germany
- Department of Applied Physics , Aalto University , P.O. Box 11100, 00076 Aalto , Finland
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Wang X, Wang C, Chen C, Duan H, Du K. Free-standing Monatomic Thick Two-dimensional Gold. NANO LETTERS 2019; 19:4560-4566. [PMID: 31241953 DOI: 10.1021/acs.nanolett.9b01494] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Monolayer metal membranes have attracted research attention owing to their fascinating physical properties. Unlike layered materials with weak interlayer van der Waals bonding, metallic monolayer membranes are difficult to exfoliate due to strong metallic bonding between layers. Here, we fabricate free-standing monatomic-thick Au membranes and nanoribbons framed in bulk crystals using in situ dealloying inside transmission electron microscope. The Au membranes are robust under high energy electron beam. Monatomic-thick nanoribbons with a minimal width of 0.6 nm are observed. First-principles calculations reveal that zigzag-edged nanoribbons are ferromagnetic with magnetic moments ranging 0.38-0.51 μB per unit-cell for a width less than 0.9 nm. In addition, a linear relationship between the bond length and the coordination number of atoms is directly investigated using atomic resolution images of monolayer and bilayer Au membranes. This work provides a pathway for direct fabrication of metal membranes and nanoribbons and to achieve novel physical properties.
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Affiliation(s)
- Xuelu Wang
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016 , China
- School of Materials Science and Engineering , University of Science and Technology of China , Shenyang 110016 , China
| | - Chunyang Wang
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Chunjin Chen
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016 , China
- School of Materials Science and Engineering , University of Science and Technology of China , Shenyang 110016 , China
| | - Huichao Duan
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016 , China
- School of Materials Science and Engineering , University of Science and Technology of China , Shenyang 110016 , China
| | - Kui Du
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016 , China
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Chen Q, He K, Robertson AW, Kirkland AI, Warner JH. Atomic Structure and Dynamics of Epitaxial 2D Crystalline Gold on Graphene at Elevated Temperatures. ACS NANO 2016; 10:10418-10427. [PMID: 27934079 DOI: 10.1021/acsnano.6b06274] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The atomic level dynamics of gold on graphene is studied at temperatures up to 800 °C using an in situ heating holder within an aberration-corrected transmission electron microscope. At this high temperature, individual gold atoms and nanoclusters are mobile across the surface of graphene and attach to defect sites and migrate along the edges of holes in graphene. Gold nanoclusters on clean graphene show crystallinity at temperatures above their predicted melting point for equivalent sized clusters due to strong epitaxial interactions with the underlying graphene lattice. Gold nanoclusters anchored to defect sites in graphene exhibit discrete rotations between fixed orientations while maintaining epitaxial correlations to the graphene. We show that gold nanoclusters can be two-dimensional with monolayer thickness and switch their crystal structure between two different phases. These results have important implications on the use of gold nanoclusters on graphene at elevated temperatures for applications, such as catalysis and plasmonics.
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Affiliation(s)
- Qu Chen
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
| | - Kuang He
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
| | - Alex W Robertson
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
| | - Angus I Kirkland
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford, OX1 3PH, United Kingdom
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