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Jun Li - One of the best experts on this subject based on the ideXlab platform.

  • constructing high loading single atom cluster catalysts via an Electrochemical Potential window strategy
    Journal of the American Chemical Society, 2020
    Co-Authors: Hai Xiao, Jun Li
    Abstract:

    Single-atom catalysts (SACs) and single-cluster catalysts (SCCs) are the new frontier of heterogeneous catalysis, which exhibit high activity, selectivity, stability, and atomic efficiency as well as precise tunability. However, the lack of efficient methods for producing high-loading and high-purity SACs and SCCs hinders their industrial applications. In this work, we propose a general and efficient strategy for the production of high-loading and high-purity SACs and SCCs anchored on suitable substrates. Our strategy relies on the existence of an Electrochemical Potential window (EcPW) we predict within which any aggregate forms of the target metal on the substrate are leached away by Electrochemical oxidation, while the strongly bound single atoms or single clusters remain at the substrate. We demonstrate the applicability of this strategy with modeling the production of Pt, Pd, and Ni SACs anchored on N-doped graphene and Fe2O3 as well as Pt3 and Ni3 SCCs anchored on graphdiyne.

Patrick P Mercier - One of the best experts on this subject based on the ideXlab platform.

Kei Murakoshi - One of the best experts on this subject based on the ideXlab platform.

  • Mechanical fabrication of metal nano-contacts showing conductance quantization under Electrochemical Potential control
    Physica E: Low-dimensional Systems and Nanostructures, 2020
    Co-Authors: Manabu Kiguchi, Tatsuya Konishi, Shinichi Miura, Kei Murakoshi
    Abstract:

    We have mechanically fabricated Ni and Cu nano constrictions in solution, and studied their electrical conductance under the Electrochemical Potential control. Conductance quantization can be observed with both metals. This is the first observation of the conductance quantization behavior for non-gold metal nano constrictions, which are mechanically fabricated in solution at room temperature. The conductance of Cu was quantized in units of G0 (=2e2/h), and a sharp 1 G0 peak is observed in the conductance histogram. For Ni, a conductance plateau showed a slightly negative slope, and a broad peak at 1~1.5 G0 was observed in the histogram. The conductance quantization behavior was discussed by comparing the result of nano constrictions fabricated in non-solution condition, with those fabricated by an Electrochemical method. It is suggested that a certain atomic configuration was stabilized in solution under the Electrochemical Potential control

  • Sensitive Raman Probe of Electronic Interactions between Monolayer Graphene and Substrate under Electrochemical Potential Control
    ACS omega, 2018
    Co-Authors: Ruifeng Zhou, Hiro Minamimoto, Satoshi Yasuda, Kei Murakoshi
    Abstract:

    In situ Electrochemical Raman spectroscopic measurements of defect-free monolayer graphene on various substrates were performed under Electrochemical Potential control. The G and 2D Raman band wavenumbers (ωG, ω2D) of graphene were found to depend upon the Electrochemical Potential, i.e., the charge density of graphene. The values of ωG and ω2D also varied depending on the choice of substrates. On metal substrates where graphene was synthesized by chemical vapor deposition, a strong blue shift of ω2D was induced, which could not account for the strain and charge doping. We attributed the blue shift of ω2D to a change in the electronic properties of graphene induced by distinct electronic interactions with the metal substrates. To explain the unique characteristics in the Raman spectrum of graphene on various substrates, a novel mechanism is proposed considering reduction of the Fermi velocity in graphene owing to dielectric screening from the metal substrates.

  • Active Tuning of Strong Coupling States between Dye Excitons and Localized Surface Plasmons via Electrochemical Potential Control
    ACS Photonics, 2018
    Co-Authors: Fumiya Kato, Hiro Minamimoto, Fumika Nagasawa, Yuko S. Yamamoto, Tamitake Itoh, Kei Murakoshi
    Abstract:

    Here we report the tuning of a number of excited dye molecules that were strongly coupled with the localized surface plasmons (LSPs) of Au nanostructures by Electrochemical Potential control. Using the redox-state-tuned dye molecules and several types of metal nanostructures with distinct LSP energies, active control of the high coupling strength was achieved via an Electrochemical Potential-based control method. One interesting finding of the present work is that the parabolic behavior of the coupling strength in the range between 0.10 and 0.27 eV is dependent on the Electrochemical Potential; this has not been observed previously. Anticrossing plots showing the energies of the upper and lower states of the coupling to the LSP energy suggest that the number of dye molecules contained in the cavity-confined LSP field is controlled not only by the redox states of the dye molecules but also by the interactions between the dyes and the metal surfaces. The present finding provides a novel route to control lig...

  • Metal atomic contact under Electrochemical Potential control
    Journal of Physics: Condensed Matter, 2012
    Co-Authors: Manabu Kiguchi, Kei Murakoshi
    Abstract:

    Electric conductance of the metal atomic contacts of Au and Pd was investigated using a scanning tunneling microscope (STM) in solution under Electrochemical Potential control. At the hydrogen evolution Potential, a fractional conductance peak appeared around 0.5 G0 (G0 = 2e2/h) in the conductance histograms of Au contacts. For Pd contacts, peaks appeared around 1.0 G0 in the conductance histograms at the hydrogen evolution Potential. The conductance behavior and atomic configuration of the metal atomic contacts at hydrogen evolution Potential were discussed based on previously reported experimental results and theoretical calculation results. We have proposed the formation of hydrogen adsorbed metal Au and Pd contacts in solution at the hydrogen evolution Potential.

  • Electrical conductance of Rh atomic contacts under Electrochemical Potential control
    Physical Review B, 2010
    Co-Authors: Tatsuya Konishi, Manabu Kiguchi, Kei Murakoshi
    Abstract:

    The electric conductance of Rh atomic contacts was investigated under the Electrochemical Potential control. The conductance histogram of Rh atomic contacts varied with the Electrochemical Potential. When the Electrochemical Potential of the contact was kept at $\Phi_{0}$= 0.1 V vs. Ag/AgCl (Rh Potential), the conductance histogram did not show any features. At $\Phi_{0}$= -0.1 V (under Potential deposited hydrogen Potential), the conductance histogram showed a feature around 2.3 $G_{0}$ ($G_{0}$ =2$e^{2}/h$), which agreed with the conductance value of a clean Rh atomic contact, which was observed in ultrahigh vacuum at low temperature. At $\Phi_{0}$= -0.25 V (over Potential deposited hydrogen Potential), the conductance histogram showed features around 0.3 and 1.0 $G_{0}$. The conductance behavior of the Rh atomic contact was discussed by comparing previously reported results of other metals, Au, Ag, Cu, Pt, Pd, Ni, Co, and Fe. The conductance behavior of the metal atomic contacts related with the strength of the interaction between hydrogen and metal surface.

R J Gutmann - One of the best experts on this subject based on the ideXlab platform.

  • Electrochemical Potential measurements during the chemical mechanical polishing of copper thin films
    Journal of The Electrochemical Society, 1995
    Co-Authors: Joseph M Steigerwald, D J Duquette, S P Murarka, R J Gutmann
    Abstract:

    A description is given of the mixed Electrochemical Potential measured in situ during the chemical-mechanical polishing of copper. Potential measurements are indicative of the dissolution rate of copper and of the equilibrium form of the polished copper by-products. These measurements are used to explain the polish performance in several ammonia-based slurries. Specifically, the polish rate is shown to correlate with the Potential and the change in Potential during polishing. In addition, complexing of copper ions with dissolved ammonia is discussed and shown to be an effective method for increasing the solubility of copper ions in the slurry and thereby increasing the polish rate.

  • Electrochemical Potential Measurements during the Chemical‐Mechanical Polishing of Copper Thin Films
    Journal of The Electrochemical Society, 1995
    Co-Authors: Joseph M Steigerwald, D J Duquette, S P Murarka, R J Gutmann
    Abstract:

    A description is given of the mixed Electrochemical Potential measured in situ during the chemical-mechanical polishing of copper. Potential measurements are indicative of the dissolution rate of copper and of the equilibrium form of the polished copper by-products. These measurements are used to explain the polish performance in several ammonia-based slurries. Specifically, the polish rate is shown to correlate with the Potential and the change in Potential during polishing. In addition, complexing of copper ions with dissolved ammonia is discussed and shown to be an effective method for increasing the solubility of copper ions in the slurry and thereby increasing the polish rate.

J S Bunch - One of the best experts on this subject based on the ideXlab platform.

  • fractional conductance quantization in metallic nanoconstrictions under Electrochemical Potential control
    Physical Review Letters, 2000
    Co-Authors: Cuihong Li, Huixin He, A Bogozi, J S Bunch
    Abstract:

    We study the electrical conductance of gold nanoconstrictions by controlling the Electrochemical Potential. At positive Potentials, the conductance is quantized near integer multiples of G0 2e2 h as shown by well-defined peaks in the conductance histogram. Below a certain Potential, however, additional peaks near 0.5G0 and 1.5G0 appear in the histogram. The fractional conductance steps are as stable and well defined as the integer steps. The experimental data are discussed in terms of Electrochemical-Potentialinduced defect scattering and Fermi energy shift, but a complete theory of the phenomenon is yet to be developed.