Sung-Joo Hwang

Abstract Highly efficient, visible‐light‐induced H 2 generation can be achieved without the help of a Pt cocatalyst by new hybrid photocatalysts, in which CdS quantum dots (QDs) (particle size ≈2.5 nm) are incorporated in the porous assembly of sub‐nanometer‐thick layered titanate nanosheets. Due to the very‐limited crystal dimension of component semiconductors, the electronic structure of CdS QDs is strongly coupled with that of the layered titanate nanosheets, leading to an efficient electron

In this study, a comprehensive characterization of iron oxide nanoparticles synthesized by using a simple one-pot thermal decomposition route is presented. In order to obtain monodisperse magnetite nanoparticles with high saturation magnetization, close to the bulk material, the molar ratios between the starting materials (solvents, reducing agents, and surfactants) were varied. Two out of nine conditions investigated in this study resulted in monodisperse iron oxide nanoparticles with high satu

A novel pillaring procedure has been developed to prepare TiO2-pillared layered titanate with large surface area, high thermal stability, and enhanced photocatalytic activity.

2D/3D hybrid cell culture systems are constructed by increasing the temperature of the thermogelling poly(ethylene glycol)‐poly( l ‐alanine) diblock copolymer (PEG‐ l ‐PA) aqueous solution in which tonsil tissue‐derived mesenchymal stem cells and graphene oxide (GO) or reduced graphene oxide (rGO) are suspended, to 37 °C. The cells exhibit spherical cell morphologies in 2D/3D hybrid culture systems of GO/PEG‐ l ‐PA and rGO/PEG‐ l ‐PA by using the growth medium. The cell proliferations are 30%–50

Mesoporous nanocomposites of Pt-reduced graphene oxide (RGO)-layered titanate are synthesized by the reaction of a mixture of exfoliated layered titanate nanosheets, graphene oxide nanosheets, and H2PtCl6 with NaBH4 to investigate the effect of layered metal oxide nanosheets on the electrocatalyst performance of Pt–RGO nanocomposites. The obtained ternary nanocomposites are composed of a porous stacking assembly of layered titanate/RGO nanosheets with well-dispersed Pt nanocrystals whose particl

The c-axis tunneling properties of both pristine Bi2212 and its HgBr 2 intercalate have been measured in the temperature range 4.2-250 K. Lithographically patterned 7-10 unit-cell heigh mesa structures on the surfaces of these single crystals were investigated. Clear SIS-like tunneling curves for current applied in the c-axis direction have been observed. The dynamic conductance d I/ d V(V) shows both sharp peaks corresponding to a superconducting gap edge and a dip feature beyond the gap, follo

The nanoscale hybridization of titanium oxide with copper oxide was carried out to control the phase transformation behavior of titanium oxide and develop a new photocatalyst active in visble light. Analysis by X-ray diffraction, electron microscopy, and nitrogen adsorption-desorption isotherm to gauge pore size distribution showed that intercalative hybridization between copper oxide and titanium oxide produced a mesoporous layer-by-layer interstratified heterostructure with a repeating distanc

A systematic application of intercalation techniques to layered superconducting oxides enables us to open a new chapter in the development of nano-hybrids with various functions. Recently we were successful in preparing a new series of inorganic-inorganic nano-hybrids, M-X-Bi 2 Sr 2 Ca m–1 Cu m O y (M=Hg, Ag, Au; X=Br, I; m=1-3) and organic-inorganic ones, R 2 HgI 4 -Bi 2 Sr 2 Ca m–1 Cu m O y (R=organic cation). Our synthetic strategies are based on (1) HSAB (hard-soft acid-base) interactions an

Micro-Raman spectroscopic analyses have been performed for the layered <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="ML1" overflow="scroll"> <mml:msub> <mml:mi mathvariant="normal">LiMnO</mml:mi> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:math> compound and its delithiated/relithiated derivatives in order to probe the effect of Li extraction/insertion on the local structure around manganese ion in this layered material. For this purpose, we have f

When Bi 2 O 3 was added to Li Al SiO 4 ceramics, Bi 12 SiO 20 secondary phase was formed. Since the melting temperature of Bi 12 SiO 20 ceramics is 880°C, the liquid phase is expected to form during sintering and to assist the densification of Li Al SiO 4 ceramics. When 15.0 mol% Bi 2 O 3 was added, the Li Al SiO 4 ceramics could be sintered at 900°C, and with 20.0 mol% Bi 2 O 3 they could even be sintered at 875°C. The 15.0 mol% Bi 2 O 3 ‐doped Li Al SiO 4 ceramics sintered at 900°C exhibited g

Abstract A new type of efficient CO 2 absorbent with improved thermal stability is synthesized via self‐assembly between 2D inorganic nanosheets and two kinds of 0D inorganic nanoclusters. In these self‐assembled nanohybrids, the nanoclusters of CdO and Cr 2 O 3 are commonly interstratified with layered titanate nanosheets, leading to the formation of highly microporous pillared structure with increased basicity of pore wall. The co‐pillaring of basic CdO with Cr 2 O 3 is fairly effective at inc