Monodisperse spherical Ni nanoparticles with diameters of 2 nm, 5 nm, and 7 nm were synthesized from the thermal decomposition of a Ni–oleylamine complex. Ni nanocrystal superlattices were generated via the controlled evaporation of solvent (see Figure). The nanoparticles were successfully used as catalysts for the Suzuki coupling reaction, and were readily oxidized to produce NiO nanoparticles.

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A mesostructured spinel Li 4 Ti 5 O 12 (LTO)-carbon nanocomposite (denoted asMeso-LTO-C) with large ( > 15 nm) and uniform pores is simply synthesized via block copolymer self-assembly. Exceptionally high rate capability is then demonstrated for Li-ion battery (LIB) negative electrodes. Polyisoprene-blockpoly(ethylene oxide) (PI-b -PEO) with a sp 2 -hybridized carbon-containing hydrophobic block is employed as a structure-directing agent. Then the assembled composite material is crystallized at 700 °C enabling conversion to the spinel LTO structure without loss of structural integrity. Part of the PI is converted to a conductive carbon that coats the pores of the Meso-LTO-C. The in situ pyrolyzed carbon not only maintains the porous mesostructure as the LTO is crystallized, but also improves the electronic conductivity. A Meso-LTO-C/Li cell then cycles stably at 10 C-rate, corresponding to only 6 min for complete charge and discharge, with a reversible capacity of 115 mA h g − 1 with 90% capacity retention after 500 cycles. In sharp contrast, a Bulk-LTO/Li cell exhibits only 69 mA h g − 1 at 10 C-rate. Electrochemical impedance spectroscopy (EIS) with symmetric LTO/ LTO cells prepared from Bulk-LTO and Meso-LTO-C cycled in different potential ranges reveals the factors contributing to the vast difference between the ratecapabilities. The carbon-coated mesoporous structure enables highly improved electronic conductivity and signifi cantly reduced charge transfer resistance, and a much smaller overall resistance is observed compared to Bulk-LTO. Also, the solid electrolyte interphase (SEI)-free surface due to the limited voltage window ( > 1 V versus Li/Li + ) contributes to dramatically reduced resistance.

We developed facile synthetic procedures to produce monodisperse palladium nanoparticles stabilized with various phosphine ligands by a better understanding of their coordination chemistry. Compared to small sized phosphines such as triphenylphosphine (TPP), trioctylphosphine (TOP) showed weaker coordination ability to palladium nanoparticles. This result was ascertained based on the 31 P NMR spectroscopic results of in situ generated molecular palladium complexes. Since TOP acts as a more efficient surfactant in the preparation of high quality monodisperse palladium nanoparticles than smaller sized phosphines, we conducted surfactant exchange reactions of TOP-stabilized palladium nanoparticles in order to produce monodisperse palladium nanoparticles stabilized with various other phosphines. These monodisperse nanoparticles include monodisperse Pd nanoparticles stabilized with chiral ligands and water-dispersable Pd nanoparticles.

An ordered mesoporous WO(3-x) material was employed for use as a supercapacitor electrode. This material exhibited a high rate capability and an excellent capacitance (366 μF cm(-2), 639 F cm(-3)), which were probably attributed to the large ordered mesopores, high electrical conductivity, and high material density.

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To promote the oxygen reduction reaction of metal-free catalysts, the introduction of porous structure is considered as a desirable approach because the structure can enhance mass transport and host many catalytic active sites. However, most of the previous studies reported only half-cell characterization; therefore, studies on membrane electrode assembly (MEA) are still insufficient. Furthermore, the effect of doping-site position in the structure has not been investigated. Here, we report the synthesis of highly active metal-free catalysts in MEAs by controlling pore size and doping-site position. Both influence the accessibility of reactants to doping sites, which affects utilization of doping sites and mass-transport properties. Finally, an N,P-codoped ordered mesoporous carbon with a large pore size and precisely controlled doping-site position showed a remarkable on-set potential and produced 70% of the maximum power density obtained using Pt/C.