Enhanced Catalytic Performance of Subnano Copper Oxide Particles

Abstract

Subnanoparticles (SNPs) with ultrasmall particle sizes (<1 nm) have potential to provide catalytic activity that is superior to that of nanoparticles. Size-controlled Cu n O x (n = 12, 28, and 60) materials supported on zirconia, prepared using a dendritic macromolecular reactor, exhibited increased ionicity of the Cu−O bonds with a decrease in size of the particles, which was suggested on the basis of the peak intensity in the Cu 2p 3/2 region. The polarization of the Cu−O bonds in the ultrasmall copper oxides provides size-dependent catalytic activity in aerobic oxidation of the CH 3 group bonded with aromatic rings. The smallest Cu 12 O x materials achieved an excellent large turnover number (TON = 40 206) without any significant deactivation.

Navigating Copper-Atom-Pair Structural Effect inside a Porous Organic Polymer Cavity for Selective Hydrogenation of Biomass-Derived 5-Hydroxymethylfurfural

“…51 Cu-2p3/2 binding energy peaks located at 934 and 934.4 eV, signifies the existence of Cu +2 oxidation state, are in good agreement with the previous report. 52 Herein, a positive binding energy displacement (~0.4eV) for Cu@C-POP-B in comparison with Cu@C-POP-A is noticed, which could be 53 In addition, the corresponding satellite peaks are observed at ~939, ~942.7 eV could be explained as a result of collision of emitted photoelectrons with the valence electrons which are being excited to higher energy levels for the both catalyst, signifies the presence of CuO phase. 54 As a result of this collision, the kinetic energy of the photoelectron decreases, seemed to be the main reason behind the appearance of satellite peak in higher binding energies.…”

A useful preparation of ultrasmall iron oxide particles by using arc plasma deposition

“…The preparation method for IOPs has a signicant effect on the structure and magnetic behavior of particles with similar sizes. The ultrasmall metal oxide synthesized using the DPA template showed amorphous characteristics, [45][46][47][48] whereas the IOPs prepared by the gas-phase APD method exhibited high crystallinity. However, the H c values for the IOPs in the GNP series were smaller than those for the g-Fe 2 O 3 nanoparticles of the same size and/or indicated little size dependence, 38,39 because this difference would largely contribute to the amorphous nature of the particle surface.…”

On the Roles of Electron Transfer in Catalysis by Nanoclusters and Nanoparticles

“…[37,38] Very small clusters below 1-nm in size, despite their catalytic efficiency, are less well defined, and optimal efficacy is not obtained below a certain number of atoms. In some cases, efficient catalyst clusters were designed with only a few atoms, [39][40][41][42][43][44] but the comparison of the catalytic efficiency of clusters of different very small numbers of atoms is informative for stereo-electronic parameter optimization. In particular, Yamamoto and his group have elegantly and successfully designed very small dendrimerstabilized clusters and shown the optimal number of atoms for catalytic efficiency in several cases (Figure 2).…”

“…In particular, Yamamoto and his group have elegantly and successfully designed very small dendrimerstabilized clusters and shown the optimal number of atoms for catalytic efficiency in several cases (Figure 2). [43,44] Finally, the ultimate lowering of the number of metals in catalysis is reached with single-atom catalysts first designed 10 years ago with great catalytic efficiency. [45][46][47] In the same way as organometallic and inorganic mononuclear homogeneous catalysts are defined by their ancillary and non-ancillary ligands, [48] however, single-atom catalysts are strongly dependent on the inorganic neighboring atoms of their inorganic matrix as in Basset's comparable surface organometallic catalysis.…”