Freestanding Single-Atom-Layer Pd-Based Catalysts: Oriented Splitting of Energy Bands for Unique Stability and Activity

Since its conception 15 years ago the field ion microscope has remained the only device capable of imaging a specimen in atomic detail. The unique feature of seeing point defects, dislocation cores and the atomic structure of grain boundaries and precipitates made the instrument a useful tool of physical metallurgy, particularly since various in-situ treatments and the capability of dissecting the specimen atom layer by atom layer with the help of controlled field evaporation made the bulk structure accessible. As different atoms look very much alike, a way of identifying them was needed. The most unambiguous identification, by mass spectrometry, has now been obtained with the atom-probe FIM. A single atom, as seen in the million times magnified image, can be chosen by the microscopist, picked up and sent through a mass spectrometer.

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Unconventional superconductivity in the single-atom-layer alloy Si(111)−√3×√3−(Tl,Pb)

Physical Review B ◽

10.1103/physrevb.98.134505 ◽

2018 ◽

Vol 98 (13) ◽

Cited By ~ 3

Author(s):

T. Nakamura ◽

H. Kim ◽

S. Ichinokura ◽

A. Takayama ◽

A. V. Zotov ◽

...

Keyword(s):

Single Atom ◽

Unconventional Superconductivity ◽

Atom Layer

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Sample Preparation Using Graphene-Oxide-Derived Nanomaterials for the Extraction of Metals

Molecules ◽

10.3390/molecules25102411 ◽

2020 ◽

Vol 25 (10) ◽

pp. 2411 ◽

Cited By ~ 4

Author(s):

Natalia Manousi ◽

Erwin Rosenberg ◽

Eleni A. Deliyanni ◽

George A. Zachariadis

Keyword(s):

Graphene Oxide ◽

Metal Ions ◽

Environmental Remediation ◽

Deep Eutectic Solvents ◽

Food Samples ◽

Single Atom ◽

Functionalized Graphene Oxide ◽

Heterogenous Catalysis ◽

Analytical Technique ◽

Atom Layer

Graphene oxide is a compound with a form similar to graphene, composed of carbon atoms in a sp2 single-atom layer of a hybrid connection. Due to its significant surface area and its good mechanical and thermal stability, graphene oxide has a plethora of applications in various scientific fields including heterogenous catalysis, gas storage, environmental remediation, etc. In analytical chemistry, graphene oxide has been successfully employed for the extraction and preconcentration of organic compounds, metal ions, and proteins. Since graphene oxide sheets are negatively charged in aqueous solutions, the material and its derivatives are ideal sorbents to bind with metal ions. To date, various graphene oxide nanocomposites have been successfully synthesized and evaluated for the extraction and preconcentration of metal ions from biological, environmental, agricultural, and food samples. In this review article, we aim to discuss the application of graphene oxide and functionalized graphene oxide nanocomposites for the extraction of metal ions prior to their determination via an instrumental analytical technique. Applications of ionic liquids and deep eutectic solvents for the modification of graphene oxide and its functionalized derivatives are also discussed.

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Planar hexagonal B36 as a potential basis for extended single-atom layer boron sheets

Nature Communications ◽

10.1038/ncomms4113 ◽

2014 ◽

Vol 5 (1) ◽

Cited By ~ 416

Author(s):

Zachary A. Piazza ◽

Han-Shi Hu ◽

Wei-Li Li ◽

Ya-Fan Zhao ◽

Jun Li ◽

...

Keyword(s):

Single Atom ◽

Potential Basis ◽

Boron Sheets ◽

Atom Layer

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Amorphizing noble metal for single-atom-layer catalysis

10.21203/rs.3.rs-122389/v1 ◽

2020 ◽

Author(s):

Yongmin He ◽

Liren Liu ◽

Chao Zhu ◽

Prafful Golani ◽

Bonhyeong Koo ◽

...

Keyword(s):

Current Density ◽

Noble Metals ◽

Rational Design ◽

High Current Density ◽

Amorphous Layer ◽

Industrial Applications ◽

Atomic Scale ◽

Utilization Efficiency ◽

Single Atom ◽

Atom Layer

Abstract Rational design of noble catalysts with a potential to leverage efficiency at the atomic scale is vital for industrial applications. Such an ultimate atom-utilization efficiency can be achieved when all noble atoms exclusively contribute to catalysis. Here, we demonstrate a scalable synthesis of freestanding amorphous PtSex (where 1.2 < x < 1.3) layers acting as single-atom-layer of Pt catalysts with an unprecedentedly high atom-utilization efficiency (~ 30 wt%) at the monolayer limit. The amorphous PtSex behaviors a fully-activated surface accessible to catalytic reactions. The catalytic performance of the amorphous layer is featured by a nearly 100% current density relative to a pure Pt surface and reliable production of sustained high-flux hydrogen over a 2-inch sized wafer sample as a proof-of-concept. Furthermore, an electrolyser using the PtSex amorphous layer as a cathode is demonstrated to generate a high current density of 1000 mA cm− 2. Such an amorphization strategy is potentially extendable to other noble metals, including Pd, Ir, Os, Rh, and Ru elements, demonstrating the universality of single-atom-layer catalysts.

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Single Atom Image Contrast in Fixed Beam Dark Field Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051840 ◽

1974 ◽

Vol 32 ◽

pp. 366-367

Author(s):

Wah Chi

Keyword(s):

Scattering Amplitude ◽

Present Report ◽

Dark Field ◽

Image Contrast ◽

Single Atom ◽

Optical Theorem ◽

Hartree Fock ◽

Heavy Atoms ◽

Beam Stop ◽

Fixed Beam

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.

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