Hongkyu Kang

Monodisperse Pt and PtRu/C60 hybrid nanoparticles for fuel cell anode catalysts

Monodisperse Pt and PtRu/C(60) hybrid nanoparticles with controlled diameters were synthesized by the reduction of metal precursors in the presence of C(60); the resulting metal/C(60) hybrid nanocatalyst exhibited a remarkable enhancement of methanol oxidation activity over commercial E-TEK catalysts.

Spectroscopic identification of gas phase photofragments from coordination compound chemical vapor deposition precursors

Abstract This review focuses on the gas phase photochemical fragmentation processes of coordination compounds that are precursors for the laser driven synthesis of solid-state materials such as thin films and nanoclusters from the gas phase. Specific emphasis is placed on the identification of photofragments by luminescence spectroscopy during the deposition process. In several cases, results from mass spectroscopy and from photofragmentation under the collision-free conditions of a molecular beam are included to clarify the identifications and mechanisms. Detailed experimental measurements have been made on metal diketonates, metal amides, metal xanthates and metal thiocarbamates. These compounds are useful as molecular precursors for the synthesis of thin films and nanoparticles of metals, binary and ternary materials, and semiconductor films.

Selective catalytic activity of ball-shaped Pd@MCM-48 nanocatalysts

Remarkable selectivity is achieved in the cleavage of benzyl ethers using ball-shaped palladium nanocatalysts, Pd@MCM-48, in an MCM-48 matrix. The unique nanocatalysts not only feature unprecedented complete hydrogenolysis selectivity of a benzyl ether over hydrogenation of a double bond, but also demonstrate selective cleavage of unsubstituted benzyl ether over substituted benzyl ethers.

Matrix-assisted synthesis of palladium nanocage and nanowires

Abstract : Our study describes the synthesis of novel nanoscale Pd cage and wires whose sizes and shapes are templated by mesoporous matrices. The templates used are cubic phase MCM-48 and hexagonal phase C(sub n)MCM-41 (n = 16, and 22), SBA-15, which have pore diameters of approx.=3, approx.=3.8, approx.=4, approx.=7, and approx.=9 nm, respectively. For PdMCM-48, the Pd metal forms spherical domains (approx.=38 nm) consisting of three dimensionally interconnected into Pd arrays; for PdSBA-15 and PdMCM-41,the Pd metal forms of one-dimensional wires. Etching out the matrix produces porous Pd cages (pore sizes of approx.=1.5 - 2.0 nin) with retaining original domain sizes of approx.=38 nm; similarly PdSBA-l5 and PdMCM-4l afford freestanding Pd nanowires. All the materials are examined by TEM, XRD, BET, and EDAX analysis. Furthermore, the thermal behavior of Pd nanowire is briefly described.