Selective synthesis of pure cobalt disulfide on reduced graphene oxide sheets and its high electrocatalytic activity for hydrogen evolution reaction

We synthesized single-phase CoS2 on a large scale by adding graphene oxide of sufficient quantity via the hydrothermal method using cobalt acetate and thioacetamide as precursors; this produced the hybrid of CoS2 with reduced graphene oxide which exhibited high electrocatalytic activity in the hydrogen evolution reaction.ope

Wavelength-selective silencing of photocurrent in Au-coated C-60 wire hybrid

A Au-coated C-60 wire device showed wavelength-selective silencing of photocurrent on illumination with 532 nm light.close6

Lateral Hopping of CO on Ag(110) by Multiple Overtone Excitation

A novel type of action spectrum representing multiple overtone excitations of the upsilon(M-C) mode was observed for lateral hopping of a CO molecule on Ag(110) induced by inelastically tunneled electrons from the tip of a scanning tunneling microscope. The yield of CO hopping shows sharp increases at 261 +/- 4 mV, corresponding to the C-O internal stretching mode, and at 61 +/- 2, 90 +/- 2, and 148 +/- 7 mV, even in the absence of corresponding fundamental vibrational modes. The mechanism of lateral CO hopping on Ag (110) was explained by the multistep excitation of overtone modes of upsilon(M-C) based on the numerical fitting of the action spectra, the nonlinear dependence of the hopping rate on the tunneling current, and the hopping barrier obtained from thermal diffusion experiments.ope

Cu2 S3 complex on Cu(111) as a candidate for mass transport enhancement

Sulfur-metal complexes, containing only a few atoms, can open new, highly efficient pathways for transport of metal atoms on surfaces. For example, they can accelerate changes in the shape and size of morphological features, such as two-dimensional nanoclusters, over time. In this study we perform STM under conditions that are designed to specifically isolate such complexes. We find a new, unexpected S-Cu complex on the Cu(111) surface, which we identify as Cu2S3. We propose that Cu2S3 enhances mass transport in this system, which contradicts a previous proposal based on Cu3S3. We analyze bonding within these Cu-S complexes, identifying a principle for stabilization of sulfur complexes on coinage metal surfaces.open44

Search for the Structure of a Sulfur-Induced Reconstruction on Cu(111)

We have carried out an extensive DFT-based search for the structure of the (√43 × √43)R ± 7.5° reconstruction of S on Cu(111), which exhibits a honeycombtype structure in scanning tunneling microscopy (STM). We apply two criteria in this search: The structure must have a reasonably low chemical potential, and it must provide a good match with STM data, both our own and the data published by Wahlström et al. Phys. Rev. B 1999, 60, 10699. The best model has 12 S adatoms and 9 Cu adatoms per unit cell. Local defects within the Cu9S12 framework, consisting of one missing or one extra Cu adatom per unit cell, would be difficult to detect with STM and would not be energetically costly. There is no obvious correlation between this model and the structure of bulk CuS. If the √43 reconstruction is viewed in terms of local building blocks, then CuS3 and CuS2 clusters, linked by shared S atoms, provides the best description.Reprinted (adapted) with permission from Journal of Physical Chemistry C 118 (2014): 29218, doi: 10.1021/jp505351g. Copyright 2014 American Chemical Society.</p

A New Analytical Method for Extracting Precise Structural Parameters of Epitaxial Graphene from Moire Patterns

A new analytical method to determine the most important two parameters, rotational angle (R theta) and strain (Delta a(Gr)/a(Gr)) of graphene on metal substrate, from scanning tunneling microscope images is presented. Epitaxial graphene on Ir(111) and Pt(111) was investigated by this method, which demonstrates that rotational angle and strain are not independent factors. Rather, these components influence each other to stabilize the graphene-metal interaction thermodynamically. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Control of Molecular Crystal Growth Pathway by Reversing Solvent Addition Order

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Synthesis of a Scalable Two-Dimensional Covalent Organic Framework by the Photon-Assisted Imine Condensation Reaction on the Water Surface

An atomically thin two-dimensional (2D) covalent organic framework (COF) was successfully synthesized via the photon-assisted imine condensation reaction within 1 h from the highly uniform and homogeneous precursor solution layer floating on the water surface. The polarity optimization of the precursor solution was the key step for the successful formation of the high-quality 2D COF because only the precursor solution consisting of polarity-controlled solvents allows ideal floating on the water surface. The polarity-controlled solution not only prohibits the agglomeration of the organic precursors on the water surface but also facilitates the wafer scale and layer number-controllable synthesis of the 2D COF. The resulting 2D COF has a uniform porous structure and highly oriented layered structure along the out-of-plane direction as observed by microscopy analysis and X-ray diffraction, respectively. In addition, we successfully fabricated field effect transistor type polyimine-based COF (pi-COF) electronic devices to demonstrate the prompt electrical responses to photo-exposure and water vapor exposure, suggesting the potential applications of the pi-COF in electrical photodetector or moisture-detector devices. © 2018 American Chemical Societ

Rapid and highly Efficient Photochemical Synthesis of Scalable Two-Dimensional Covalent Organic Framework (COF) on the Water Surface using Properly Controlled Solvent Combination

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