Hyunjoon Song

A procedure for gram-scale synthesis of monodisperse Cu2O nanocubes by a simple polyol process is demonstrated. The nanocubes are subsequently oxidized to form CuO hollow cubes, spheres, and urchin-like particles, through a sequential dissolution–precipitation process. The CuO urchin-like particles exhibited excellent electrochemical performance and stability, superior to those of hollow structures, for lithium-ion battery anode materials. Detailed facts of importance to specialist readers are p

We report the synthesis of monodisperse Pt nanocrystals with three different shapes-cubes, cuboctahedra, and octahedra, selectively, with similar sizes of 9-10 nm by a modified polyol process. We found that addition of silver ion enhances the crystal growth rate along 100, and essentially determines the shape and surface structure of the Pt nanocrystals. After the reaction, the silver species can be easily removed by repetitive precipitation giving pure Pt nanoparticles. Two-dimensional arrays o

A novel high surface area heterogeneous catalyst based on solution phase colloidal nanoparticle chemistry has been developed. Monodisperse platinum nanoparticles of 1.7-7.1 nm have been synthesized by alcohol reduction methods and incorporated into mesoporous SBA-15 silica during hydrothermal synthesis. Characterization of the Pt/SBA-15 catalysts suggests that Pt particles are located within the surfactant micelles during silica formation leading to their dispersion throughout the silica structu

For long-term storage of renewable energy, the electrochemical carbon dioxide reduction reaction (CO₂RR) offers a promising option for converting electricity to permanent forms of chemical energy. In this work, we present highly selective ethylene production dependent upon the catalyst morphology using copper oxide nanoparticles. The branched CuO nanoparticles were synthesized and then deposited on conductive carbon materials. After activation, the major copper species changed to Cu<s

Nickel-based catalysts have been good candidates for steam reforming of methane, but their stability has been restricted due to the agglomeration among particles at high temperature. In the present work, a new type of Ni@SiO2 yolk-shell nanoreactor framework comprising Ni cores inside hollow silica shells has been prepared through direct silica coating and subsequent selective etching of the metal cores. This nanoreactor framework is remarkably stable at high temperatures up to 973 K, because th

This paper presents a ZnO-CuO p-n heterojunction chemiresistive sensor that comprises CuO hollow nanocubes attached to ZnO spherical cores as active materials. These ZnO-CuO core-hollow cube nanostructures exhibit a remarkable response of 11.14 at 1 ppm acetone and 200 °C, which is a superior result to those reported by other metal-oxide-based sensors. The response can be measured up to 40 ppb, and the limit of detection is estimated as 9 ppb. ZnO-CuO core-hollow cube nanostructures also present

CuO hollow nanostructures have been used for the catalytic [3 + 2] cycloaddition of azides with terminal alkynes to provide the products in good yields with high regioselectivity.

In order to understand heterogeneous catalytic reactions, model catalysts such as a single crystalline surface have been widely studied for many decades. However, catalytic systems that actually advance the reactions are three-dimensional and commonly have multiple components including active metal nanoparticles and metal oxide supports. On the other hand, as nanochemistry has rapidly been developed and been applied to various fields, many researchers have begun to discuss the impact of nanochem

Ni@SiO(2) core-shell nanoparticles were transformed to Ni particles on silica spheres via a branched nickel phyllosilicate phase by hydrothermal and hydrogen reduction reactions; the final morphology was successfully employed as an active nanocatalyst for the hydrogen transfer reaction of acetophenone.

The evolution of the phase and morphology of FeOOH nanorods prepared by a hydrothermal method is studied via X-ray diffraction (XRD) and in situ transmission electron microscopy. The FeOOH nanorod with a tetragonal structure (β-FeOOH) is gradually converted into a rhombohedral Fe₂O₃ nanorod by a simple thermal treatment. The existence of an intermediate FeOOH structure with high lattice strains during the phase transition is identified by Rietveld analysis using XRD. The el