The strong correlations between thermal conductivities and electronic spin states in the crystals of Fe(III) spin crossover complexes.

Solids that change their thermal conductivity during a phase transition can be useful in the development of a thermal switch to allow control of heat flow and reduce energy consumption. Although a crystal of a spin crossover (SCO) complex is a representative solid with spin states correlated with heat transporting lattice vibrations, the heat transporting property of a crystal of the SCO complex during a spin state transition has not yet been reported. In this work, we report that the temperature dependence of the thermal conductivity of mononuclear Fe(III) SCO complexes is greatly affected by spin state transitions.

Mesoporous Carbon Fibers with Tunable Mesoporosity for Electrode Materials in Energy Devices.

To improve the properties of mesoporous carbon (MC), used as a catalyst support within electrodes, MC fibers (MCFs) were successfully synthesized by combining organic-organic self-assembly and electrospinning deposition and optimizing heat treatment conditions. The pore structure was controlled by varying the experimental conditions. Among MCFs, MCF-A, which was made in the most acidic condition, resulted in the largest pore diameter (4-5 nm), and the porous structure and carbonization degree were further optimized by adjusting heat treatment conditions.

Development of Porous Pt Electrocatalysts for Oxygen Reduction and Evolution Reactions.

Porous Pt electrocatalysts have been developed as an example of carbon-free porous metal catalysts in anticipation of polymer electrolyte membrane (PEM) fuel cells and PEM water electrolyzers through the assembly of the metal precursor and surfactant. In this study, porous Pt was structurally evaluated and found to have a porous structure composed of connected Pt particles. The resulting specific electrochemical surface area (ECSA) of porous Pt was 12.

Gram-scale synthesis of alkoxide-derived nitrogen-doped carbon foam as a support for Fe-N-C electrocatalysts.

Non-platinum group metal (non-PGM) catalysts for the oxygen reduction reaction (ORR) are set to reduce the cost of polymer electrolyte membrane fuel cells (PEFCs) by replacing platinum at the cathode. We previously developed unique nitrogen-doped carbon foams by template-free pyrolysis of alkoxide powders synthesized using a high temperature and high pressure solvothermal reaction. These were shown to be effective ORR electrocatalysts in alkaline media.

Encapsulating Mobile Proton Carriers into Structural Defects in Coordination Polymer Crystals: High Anhydrous Proton Conduction and Fuel Cell Application.

We describe the encapsulation of mobile proton carriers into defect sites in nonporous coordination polymers (CPs). The proton carriers were encapsulated with high mobility and provided high proton conductivity at 150 °C under anhydrous conditions. The high proton conductivity and nonporous nature of the CP allowed its application as an electrolyte in a fuel cell.

Immobilization of an Enzyme Into Nano-Space of Nanostructured Carbon and Evaluation as Electrochemical Sensors.

The aims of this study are immobilization of formaldehyde dehydrogenase (FDH) into nano-space of nanostructured carbon and evaluation as a possible sensor detecting low concentration formaldehyde. In order to understand the effect of carbon pore size on activity and stability of FDH, mesoporous carbon (MC), originally made in our lab, and commercially available ketjen black (KB) were used in this study. Enzyme activity and electrochemical sensing ability of FDH encapsulated into such two carbon materials were compared.

Enhancement of activity and stability of the formaldehyde dehydrogenase by immobilizing onto phenyl-functionalized mesoporous silica.

Formaldehyde dehydrogenase (FDH, molecular size of 8.6 nm × 8.6 nm × 19.

Fabrication of ion-induced carbon-cobalt nanocomposite fibers: effect of cobalt supply rate.

Graphite surfaces were irradiated by argon (Ar+) ions at 1 keV with a simultaneous cobalt (Co) supply at room temperature. Various kinds of carbon nanocomposites, such as nanocones with and without single nanofibers on their tops, nanorods and fish-scale-like nanoprotrusions, were formed depending on Co supply rates. It has been observed that with increasing the Co supply rate the formation of nanoprotrusions without nanofibers became prominent.

Simple methods for tuning the pore diameter of mesoporous carbon.

The organic-organic self-assembly method with Resorcinol (R)/Formaldehyde (F) and Pluronic F127 has been employed to synthesize mesoporous carbon (MC). The pore diameter of the MC has been tuned from 7 to 12.5 nm by changing the molar ratio of carbon sources to surfactant and polymerization time.

Direct fabrication of aligned metal composite carbon nanofibers on copper substrate at room temperature and their field emission property.

Direct growth of aligned metal composite carbon nanofibers (MCNFs) was achieved by a highly reproducible room temperature growth process on cost effective electrically conductive copper (Cu) substrate without any catalyst. The direct fabrication of MCNFs on electrically conductive substrate might offer new perspectives in the field of field emission displays (FEDs).

Fabrication and morphological control of ion-induced zinc nanostructures.

An efficient method for the fabrication of zinc (Zn) nanostructures (nanoneedles and nanofibers) of controllable density and morphology without any catalyst, hazardous chemicals or external heat supply has been investigated. By varying the ion irradiation time and the ion current density, morphological control and the density of Zn nanostructures were successfully achieved using a fast and viable ion irradiation technique. Scanning (SEM) and transmission electron microscopy (TEM) results revealed that the sputtered surface was almost entirely covered with densely distributed conical and needle-like protrusions with linear shaped (sometimes curved) nanostructures (such as nanoneedles and nanofibers) with diameters and lengths of about 20-50 nm and several hundred nanometers, respectively.

Transparent and flexible field electron emitters based on the conical nanocarbon structures.

The fabrication of conical nanocarbon structures (CNCSs) on a transparent and flexible nafion substrate at room temperature using an ion irradiation technique and their application toward field emission displays (FEDs) have been demonstrated. The main advantage of this technique is that CNCSs can be fabricated directly on the transparent substrate while retaining the transparency of the substrate. A scanning electron microscopy (SEM) image revealed that the sputtered surface was entirely covered with CNCSs with a calculated numerical density of 6 x 10(6) /mm(2).

Preparation of a self-standing mesoporous carbon membrane with perpendicularly-ordered pore structures.

A self-standing mesoporous carbon membrane (sOMC) with perpendicularly-ordered pore structures was prepared through a simple synthetic method; the pores with a diameter of 8 nm were well ordered over a large area and perpendicularly-oriented to the surface without any external field; in the formation of this ordered structure, the drying process is key, and a porous alumina support is important to induce drying.

Metal ion assembly in macromolecules.

Self-assembled organic-inorganic hybrid nano-materials have recently received much attention due to their novel and original functions, including new electronic, optical, magnetic, and catalytic properties. Especially, reactions in organic-metallic hybrid materials are closely related to biological reactions, such as the reactions in metal-containing protein, and the controlled metal ions assembly into organic polymers becomes very important. In the first part of this review, recent progresses in two types of organic-inorganic hybrid nano-materials (Organic compounds [character: see text] inorganic mesoporous materials and Metal ions [character: see text] organic polymer) are summarized.

Sequential metal ion assembly in cyclic phenylazomethine.

[reaction: see text] Cyclic phenylazomethines with methylene spacers (CPA-M) are obtained by dehydration of diamine with diketone. During the titration of CPA-M 4mer with FeCl(3), we observe two consecutive isosbestic points in the UV-vis spectra. We conclude that complexation occurs in two consecutive steps.

Crystal chemistry of the gold (I) trimer, Au(3)(NC(5)H(4))(3): formation of hourglass figures and self-association through aurophilic attraction.

X-ray crystallography reveals that individual molecules of Au(3)(NC(5)H(4))(3) self-associate through aurophilic interactions into two distinct structural motifs that involve both extended chains of molecules connected by pairwise Au.Au contacts and individual Au.Au contacts and discrete dimers linked by pairwise Au.