Hydrothermal chemistry has been generally accepted as an effective route for new and advanced materials. The reasons for utilizing hydrothermal reactions are fundamentally based on the favourable thermodynamics and self-catalytic kinetics. In this talk, I begin with the hydrothermal foundations of thermodynamics and kinetics, followed by a general description of the hydrothermal syntheses of advanced functional materials. I emphasize on the synthesis, structure, and superior chemical and physical properties of three oxidation state manganite La1-x-yCaxKyMnO3, e.g., atomic-scale p-n junction materials, which show ideal rectification characteristic and greatly improvement for photocatalytic water oxidation than other mixed-valence state manganites. I also talk about an effective method to tailor crystal facets of many perovskite structure oxides under hydrothermal conditions, such as LaFeO3, LaCrO3 and La1-xSrxMnO3.
4:30pm - 5:00pm Invited
Self-Assembled Fullerene Nanomaterials: From Zero to Higher Dimensions
Lok Kumar SHRESTHA, Partha BAIRI, Rekha Goswami SHRESTHA, Jonathan P HILL, Katsuhiko ARIGA
National Institute for Material Science, Japan
Self-assembled crystalline fullerenes (C60 or C70) nanostructures exhibit excellent physicochemical and optoelectronic properties including high electron mobility, high photosensitivity. Owing to these appealing features together with excellent electron accepting properties, dimensionally integrated nanostructures of fullerene crystals have received considerable interest for the possible applications in diverse ﬁelds such as material engineering and device fabrications including flexible optoelectronics device, field effect transistors, light emitting diodes, photovoltaic cells, sensors, and photodetectors. On the other hand, insertion of porous structures in the fullerene crystals is expected to increase the effective surface area drastically, which is expected to offer a great utility in many applications (e.g., high-power solar cells and capacitors, large hydrogen storages, highly-active photocatalysts, highly-sensitive chemical and physical sensors). In this contribution, we present self-assembled fullerene C60 and C70 crystals from zero to higher dimensions using solution based strategy called liquid-liquid interfacial precipitation (LLIP) method under mild conditions of temperature and pressure. We also discuss the recently developed novel technique for the expansion of fullerene nanomaterials into hierarchic macro- and mesopores architectures with crystallized frameworks. These novel materials offered enhanced electrochemically active surface areas compared to pristine fullerenes. Textural properties of the materials could be flexibly controlled by adjusting the synthetic conditions. We also discuss our recent results on the thermal conversion of single crystalline fullerene nanorods and nanotubes into high surface area nanoporous carbons nanorods and nanotubes with graphitic microstructure. Graphitic carbon nanotubes and nanorods displayed enhanced electrochemical supercapacitive capacitance followed by excellent sensing performance sensitive towards aromatic solvents. Note that the C60 molecule can be regarded as an ideal zero dimensional building blocks with striking functions. Therefore, construction of zero to higher-dimensional objects, such as 1D, 2D or 3D including porous nanomaterials may realize important aspects of fullerene nanoarchitectonics.