Size- and Support-Dependent Electronic and Catalytic Properties of Au⁰/Au³⁺ Nanoparticles Synthesized from Block Copolymer Micelles

Abstract

Supported Au nanoclusters synthesized from diblock copolymer micelles can be reliably prepared with well-controlled sizes and dispersions. For particles with diameters between approximately 1 and 6 nm, the particle size and the support were found to strongly influence the oxygen reactivity, the formation and stabilization of a metal-oxide, and the catalytic activity for electrooxidation of carbon monoxide. The smallest particles studied (1.5 nm) were the most active for electrooxidation of CO and had the largest fraction of oxygen associated with gold at the surface as measured by the Au(3+)/Au(0) X-ray photoemission intensities. Conducting and semiconducting substrates, ITO-coated glass and TiO(2), respectively, were associated with greater stabilization of Au(3+) oxide as compared to insulating, SiO(2), substrates.

Nitrogen‐Doped Pt/C Electrocatalysts with Enhanced Activity and Stability toward the Oxygen Reduction Reaction

“…[17,18,29] The Raman spectra of platinum-free VC before and after the hydrazine treatment are shown in Figure S3. Interestingly, the peak shift of the G-band and the enhancement of D-band intensity were not observed.…”

Green Synthesis of Smart Metal/Polymer Nanocomposite Particles and Their Tuneable Catalytic Activities

“…This effect is attributed to the fact that the ionization potential and electron affinity values of Au atom are higher than those of the Ag atom. The large electronegativity value of the Au atom leads to effective charge transfer from silver to gold atoms because the second metal ion (Ag + ) has lower reduction potential than gold nanoparticles [27,28]. Scheme 1.…”

Combined Electrostatic-Covalent Building of Au NPs Multilayers and Their Size-Enhanced Cohesive and SERS Properties

“…This finding is in good agreement with what can be expected from size effects in such nanomaterials. Indeed, the total free volume (tetrahedral and octahedral voids) in a close-packed 2D assembly of monodisperse spherical particles (1 or 2 layers for instance) increases with the size of the particles [1,17]. As a result, one expects the cohesion of the ordered assembly of spherical particles to decrease with the increase of the Au NPs diameter.…”

“…In particular, supported nanostructured films of Au NPs have appeared as promising functional structures for applications as diverse as optical field enhancement [4,5] and catalysis [6][7][8]. Indeed, metal particles of size smaller than the wavelength of light exhibit specific optical properties due to the resonant excitation of coherent electron oscillations, a phenomenon known as localized surface plasmons.…”