Jae Sung Lee

An organic species bearing an organic sulfonic acid (HSO 3 -) was grafted onto the surface of montmorillonite (MMT) by silane condensation, and the composite membranes were cast together with Nafion. The performance of the Nafion/HSO 3 −MMT composite membranes for direct methanol fuel cells (DMFCs) was evaluated in terms of methanol permeability, proton conductivity, and cell performance. The methanol permeability of the composite membrane decreased dramatically with increasing content of HSO 3

Mesoporous tungsten carbides displayed an excellent solar conversion efficiency (7.01%) as a counter electrode for dye sensitized solar cells under 100 mW cm(-2), AM 1.5G illumination, which corresponded to ca. 85% of the efficiency of the conventional platinum electrode.

Photocatalytic activity in the water splitting of Ln 2 Ti 2 O 7 (Ln = La, Pr, Nd) with a layered structure was highly dependent on their electronic band structure. The conduction band of La 2 Ti 2 O 7 consisted mainly of Ti 3d and La 5d, whereas the valence band consisted mainly of O 2p and Ti 3d. The empty La 4f level was found to be located ca. 3.6 eV above the bottom of the conduction band from both the electronic band-structure calculation and the XPS measurement. The occupied and unoccupied

Barium titanate nanowires synthesized with a surfactant-free hydrothermal method have been characterized by various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), synchrotron X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The TEM and SEM analyses show the uniform cylindrical nanowires. The Rietveld refinement with synchrotron X-ray powder diffraction showed that the lattice parameters of cubic and tetragonal phas

Abstract The recyclable metal nanoparticle catalysts, rhodium in aluminum oxyhydroxide [Rh/AlO(OH)] and iridium in aluminum oxyhydroxide [Ir/AlO(OH)], were simply prepared from readily available reagents. The catalysts showed high activities in the hydrogenation of various arenes and ketones under mild conditions. Selective hydrogenation was possible for bicyclic and tricyclic arenes in high yields. The catalysts were active at room temperature even with a hydrogen balloon. Also, the catalysts s

We report the synthesis of porous ZnO-ZnSe nanocomposites for use in visible light photocatalysis. Porous ZnO nanostructures were synthesized by a microwave-assisted hydrothermal reaction then converted into porous ZnO-ZnSe nanocomposites by a microwave-assisted dissolution-recrystallization process using an aqueous solution containing selenium ions. ZnO and ZnSe nanocrystallites of the nanocomposites were well-mixed (rather than forming simple core-shell (ZnO-ZnSe) structures), particularly, in

Direct conversion of MoO 3 to molybdenum carbides by temperature-programmed reaction (TPR) with a reacting gas mixture of CH 4 /4H 2 has been studied in the presence of a transition metal selected from Pt, Pd, Ni, Co, Cu, and pre-synthesized Mo 2 C loaded on MoO 3 . Loading of the metals reduced the temperatures of MoO 3 reduction and increased the specific surface area of produced carbides. However, the obtained phase of molybdenum carbides differed depending on the employed transition metal; P