Robust ferromagnetism in single-atom-thick ternary chromium carbonitride CrN4C2

Resolution and contrast are the important factors to determine the feasibility of imaging single heavy atoms on a thin substrate in an electron microscope. The present report compares the atom image characteristics in different modes of fixed beam dark field microscopy including the ideal beam stop (IBS), a wire beam stop (WBS), tilted illumination (Tl) and a displaced aperture (DA). Image contrast between one Hg and a column of linearly aligned carbon atoms (representing the substrate), are also discussed. The assumptions in the present calculations are perfectly coherent illumination, atom object is represented by spherically symmetric potential derived from Relativistic Hartree Fock Slater wave functions, phase grating approximation is used to evaluate the complex scattering amplitude, inelastic scattering is ignored, phase distortion is solely due to defocus and spherical abberation, and total elastic scattering cross section is evaluated by the Optical Theorem. The atom image intensities are presented in a Z-modulation display, and the details of calculation are described elsewhere.

Atomic Spectroscopy in the FIM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145157 ◽

1986 ◽

Vol 44 ◽

pp. 758-761

Author(s):

J. J. Hren ◽

S. D. Walck

Keyword(s):

Electron Microscope ◽

Electric Fields ◽

Atom Probe ◽

Atomic Spectroscopy ◽

Single Atom ◽

Statistical Sampling ◽

Commercial Instrument ◽

Available Technology ◽

High Electric Fields ◽

Field Ion Microscope

The field ion microscope (FIM) has had the ability to routinely image the surface atoms of metals since Mueller perfected it in 1956. Since 1967, the TOF Atom Probe has had single atom sensitivity in conjunction with the FIM. “Why then hasn't the FIM enjoyed the success of the electron microscope?” The answer is closely related to the evolution of FIM/Atom Probe techniques and the available technology. This paper will review this evolution from Mueller's early discoveries, to the development of a viable commercial instrument. It will touch upon some important contributions of individuals and groups, but will not attempt to be all inclusive. Variations in instrumentation that define the class of problems for which the FIM/AP is uniquely suited and those for which it is not will be described. The influence of high electric fields inherent to the technique on the specimens studied will also be discussed. The specimen geometry as it relates to preparation, statistical sampling and compatibility with the TEM will be examined.

Field ion microscope investigations of atomic processes at surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153117 ◽

1989 ◽

Vol 47 ◽

pp. 228-229

Author(s):

G. L. Kellogg ◽

P. R. Schwoebel

Keyword(s):

Single Crystal ◽

Crystal Surface ◽

Linear Chain ◽

Atom Probe ◽

Nucleation And Growth ◽

Single Atom ◽

Initial Structure ◽

Atomic Processes ◽

Single Crystal Surfaces ◽

Field Ion Microscope

Although no longer unique in its ability to resolve individual single atoms on surfaces, the field ion microscope remains a powerful tool for the quantitative characterization of atomic processes on single-crystal surfaces. Investigations of single-atom surface diffusion, adatom-adatom interactions, surface reconstructions, cluster nucleation and growth, and a variety of surface chemical reactions have provided new insights to the atomic nature of surfaces. Moreover, the ability to determine the chemical identity of selected atoms seen in the field ion microscope image by atom-probe mass spectroscopy has increased or even changed our understanding of solid-state-reaction processes such as ordering, clustering, precipitation and segregation in alloys. This presentation focuses on the operational principles of the field-ion microscope and atom-probe mass spectrometer and some very recent applications of the field ion microscope to the nucleation and growth of metal clusters on metal surfaces.The structure assumed by clusters of atoms on a single-crystal surface yields fundamental information on the adatom-adatom interactions important in crystal growth. It was discovered in previous investigations with the field ion microscope that, contrary to intuition, the initial structure of clusters of Pt, Pd, Ir and Ni atoms on W(110) is a linear chain oriented in the <111> direction of the substrate.

Recent advancement in the electrocatalytic synthesis of ammonia

Nanoscale ◽

10.1039/d0nr01359e ◽

2020 ◽

Vol 12 (15) ◽

pp. 8065-8094 ◽

Cited By ~ 6

Author(s):

Xudong Wen ◽

Jingqi Guan

Keyword(s):

Metal Oxide ◽

Oxide Catalysts ◽

Single Atom ◽

Metal Oxide Catalysts ◽

Metal Free ◽

Recent Advancement ◽

Nanocomposite Catalysts

Different kinds of electrocatalysts used in NRR electrocatalysis (including single atom catalysts, metal oxide catalysts, nanocomposite catalysts, and metal free catalysts) are introduced.

Rational prediction of multifunctional bilayer single atom catalysts for the hydrogen evolution, oxygen evolution and oxygen reduction reactions

Nanoscale ◽

10.1039/d0nr05202g ◽

2020 ◽

Vol 12 (39) ◽

pp. 20413-20424

Author(s):

Riming Hu ◽

Yongcheng Li ◽

Fuhe Wang ◽

Jiaxiang Shang

Keyword(s):

Oxygen Reduction ◽

Hydrogen Evolution ◽

Oxygen Evolution ◽

Single Atom ◽

Reduction Reactions ◽

Oxygen Reduction Reactions

Bilayer single atom catalysts can serve as promising multifunctional electrocatalysts for the HER, ORR, and OER.

SINGLE ATOM DETECTABILITY OF A ToF ATOM-PROBE

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1984957 ◽

1984 ◽

Vol 45 (C9) ◽

pp. C9-343-C9-347 ◽

Cited By ~ 1

Author(s):

T. Sakurai ◽

T. Hashizume ◽

A. Jimbo

Keyword(s):

Atom Probe ◽

Single Atom

Tunable Carbon Surface from Mono- to Multi-Metallic Single Atoms

10.26434/chemrxiv.12264083 ◽

2020 ◽

Author(s):

Weihong Lai ◽

Heng Wang ◽

Quan jiang ◽

Zichao Yan ◽

Hanwen Liu ◽

...

Keyword(s):

Synergistic Effects ◽

Structural Evolution ◽

Charge Compensation ◽

Catalytic Reactions ◽

Single Atom ◽

Carbon Surface ◽

Hydrogen Electrode ◽

Single Atoms ◽

Mass Activity ◽

Co Doped

Herein, we develop a non-selective charge compensation strategy to prepare multi-single-atom doped carbon (MSAC) in which a sodium p-toluenesulfonate (PTS-Na) doped polypyrrole (S-PPy) polymer is designed to anchor discretionary mixtures of multiple metal cations, including iron (Fe3+), cobalt (Co3+), ruthenium (Ru3+), palladium (Pd2+), indium (In3+), iridium (Ir2+), and platinum (Pt2+) . As illustrated in Figure 1, the carbon surface can be tuned with different level of compositional complexities, including unary Pt1@NC, binary (MSAC-2, (PtFe)1@NC), ternary (MSAC-3, (PtFeIr)1@NC), quaternary (MSAC-4, (PtFeIrRu)1@NC), quinary (MSAC-5, (PtFeIrRuCo)1@NC), senary (MSAC-6, (PtFeIrRuCoPd)1@NC), and septenary (MSAC-7, (PtFeIrRuCoPdIn)1@NC) samples. The structural evolution of carbon surface dictates the activities of both ORR and HER. The senary MSAC-6 achieves the ORR mass activity of 18.1 A·mgmetal-1 at 0.9 V (Vs reversible hydrogen electrode (RHE)) over 30K cycles, which is 164 times higher than that of commercial Pt/C. The quaternary MSAC-4 presented a comparable HER catalytic capability with that of Pt/C. These results indicate that the highly complexed carbon surface can enhance its ability over general electrochemical catalytic reactions. The mechanisms regarding of the ORR and HER activities of the alternated carbon surface are also theoretically and experimentally investigated in this work, showing that the synergistic effects amongst the co-doped atoms can activate or inactivate certain single-atom sites.

Development of the ChIMES Force Field for Reactive Molecular Systems: Carbon Monoxide at Extreme Conditions

10.26434/chemrxiv.7940810.v1 ◽

2019 ◽

Author(s):

Rebecca Lindsey ◽

Nir Goldman ◽

Laurence E. Fried ◽

Sorin Bastea

Keyword(s):

Carbon Monoxide ◽

Molecular System ◽

Interaction Model ◽

System Size ◽

Single Atom ◽

Reactive System ◽

Extreme Conditions ◽

Ambient Conditions ◽

Molecular Systems ◽

Three Body

The interatomic Chebyshev Interaction Model for Efficient Simulation (ChIMES) is based on linear combinations of Chebyshev polynomials describing explicit two- and three-body interactions. Recently, the ChIMES model has been developed and applied to a molten metallic system of a single atom type (carbon), as well as a non-reactive molecular system of two atom types at ambient conditions (water). Here, we continue application of ChIMES to increasingly complex problems through extension to a reactive system. Specifically, we develop a ChIMES model for carbon monoxide under extreme conditions, with built-in transferability to nearby state points. We demonstrate that the resulting model recovers much of the accuracy of DFT while exhibiting a 104increase in efficiency, linear system size scalability and the ability to overcome the significant system size effects exhibited by DFT.

Engineering Electronic Structure of Single-Atom Pd Site on Ti 0.87 O 2 Nanosheet via Charge Transfer Enables C-Br Cleavage for Room Temperature Suzuki Coupling

CCS Chemistry ◽

10.31635/ccschem.20.202000388 ◽

2020 ◽

pp. 1-29

Author(s):

Yangxin Jin ◽

Fei Lu ◽

Ding Yi ◽

Junmeng Li ◽

Fengchu Zhang ◽

...

Keyword(s):

Electronic Structure ◽

Charge Transfer ◽

Room Temperature ◽

Suzuki Coupling ◽

Single Atom

Alumina-Supported Palladium–Silver Bimetallic Catalysts with Single-Atom Pd1 Sites in the Liquid-Phase Hydrogenation of Substituted Alkynes

Kinetics and Catalysis ◽

10.1134/s0023158420060129 ◽

2020 ◽

Vol 61 (6) ◽

pp. 869-878

Author(s):

A. V. Rassolov ◽

G. O. Bragina ◽

G. N. Baeva ◽

I. S. Mashkovsky ◽

A. Yu. Stakheev

Keyword(s):

Liquid Phase ◽

Bimetallic Catalysts ◽

Single Atom ◽

Liquid Phase Hydrogenation ◽

Supported Palladium ◽

Palladium Silver