Nam, Ki Tae

The selection and assembly of materials are central issues in the development of smaller, more flexible batteries. Cobalt oxide has shown excellent electrochemical cycling properties and is thus under consideration as an electrode for advanced lithium batteries. We used viruses to synthesize and assemble nanowires of cobalt oxide at room temperature. By incorporating gold-binding peptides into the filament coat, we formed hybrid gold-cobalt oxide wires that improved battery capacity. Combining v

The development of a water oxidation catalyst has been a demanding challenge in realizing water splitting systems. The asymmetric geometry and flexible ligation of the biological Mn4CaO5 cluster are important properties for the function of photosystem II, and these properties can be applied to the design of new inorganic water oxidation catalysts. We identified a new crystal structure, Mn3(PO4)2·3H2O, that precipitates spontaneously in aqueous solution at room temperature and demonstrated its hi

Organolead halide perovskites are used for low-operating-voltage multilevel resistive switching. Ag/CH3 NH3 PbI3 /Pt cells exhibit electroforming-free resistive switching at an electric field of 3.25 × 10(3) V cm(-1) for four distinguishable ON-state resistance levels. The migration of iodine interstitials and vacancies with low activation energies is responsible for the low-electric-field resistive switching via filament formation and annihilation.

Abstract The electrocatalytic conversion of CO 2 to value‐added hydrocarbons is receiving significant attention as a promising way to close the broken carbon‐cycle. While most metal catalysts produce C 1 species, such as carbon monoxide and formate, the production of various hydrocarbons and alcohols comprising more than two carbons has been achieved using copper (Cu)‐based catalysts only. Methods for producing specific C 2 reduction outcomes with high selectivity, however, are not available thu

A concave rhombic dodecahedron (RD) gold nanoparticle was synthesized by adding 4-aminothiophenol (4-ATP) during growth from seeds. This shape is enclosed by stabilized facets of various high-indexes, such as (331), (221), and (553). Because it is driven thermodynamically and stabilized by 4-ATP ligands, the concave RD maintains its structure over a few months, even after rigorous electrochemical reactions. We discussed the mechanism of the shape evolution controlled by 4-ATP and found that both

Chiral plasmonic nanostructures have opened up unprecedented opportunities in optical applications. We present chirality evolution in nanoparticles focusing on the crystallographic aspects and elucidate key parameters for chiral structure formation. From a detailed understanding of chirality formation, we achieved a morphology (432 Helicoid IV) of three-dimensionally controlled chiral plasmonic nanoparticles based on the rhombic dodecahedral shape. The role of the synthesis parameters, seed, cys

The synthesis of pure whitlockite (WH: Ca18Mg2(HPO4)2(PO4)12) has remained a challenge even though it is the second most abundant inorganic in living bone. Although a few reports about the precipitation of WH in heterogeneous phases have been published, to date, synthesizing WH without utilizing any effects of a buffer or various other ions remains difficult. Thus, the related research fields have encountered difficulties and have not been fully developed. Here, we developed a large-scale synthe

For the efficient electroconversion of CO 2 to formate, CO and H 2 evolution must be suppressed. Herein, carbon-supported BiO x nanoparticles (BiO x /C) were investigated as a potential candidate for CO 2 reduction. In bicarbonate solutions, the BiO x /C catalysts exhibited a high Faradaic efficiency of 93.4% for formate from −1.37 to −1.70 V versus Ag/AgCl with a negligible amount of CO and H 2 . Stable partial current densities and high Faradaic efficiencies were also achieved in 0.5 M NaCl (1

From small molecules to entire organisms, evolution has refined biological structures at the nanoscale, microscale and macroscale to be chiral—that is, mirror dissymmetric. Chirality results in biological, chemical and physical properties that can be influenced by circularly polarized electromagnetic fields. Chiral nanoscale materials can be designed that mimic, refine and advance biological chiral geometries, to engineer optical, physical and chemical properties for applications in photonics, s

A high CO₂ to CO electroreduction rate exceeding 300 mA cm⁻² was achieved with single atom nickel and nitrogen doped three-dimensional porous carbon electrocatalysts.