Shingo Morimoto

Carbon-supported Pt–Ru nanoparticles prepared in glyoxylate-reduction system promoting precursor–support interaction

A high dispersion of carbon-supported Pt–Ru alloy nanoparticles have been prepared in an alkaline aqueous solution by using glyoxylate as a reducing agent. The glyoxylate monoanion is converted to oxalate dianion with the reduction of metal precursor ions. The surface-potential analysis of unsupported Pt–Ru black in the presence of all the anion species coexistent in the preparation system suggests a possibility of oxalate dianion as the most effective particle stabilizer. In the glyoxylate-reduction system, a precursor–support interaction is significantly promoted to affect the formation and stabilization of nanoparticles. The glyoxylate reduction at 20-wt% metal loading has provided a higher Pt(0)/Ru concentration ratio in the near-surface region than that of 60-wt% catalyst. The structural and morphological features and advantageous surface composition of the 20-wt% catalyst contribute to the high mass activity for methanol oxidation in the anode overpotential range of typical direct methanol fuel cells.

Corrigendum: Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors

Nitrogen-doped porous activated carbon monoliths (NDP-ACMs) have long been the most desirable materials for supercapacitors. Unique to the conventional template based Lewis acid/base activation methods, herein, we report on a simple yet practicable novel approach to production of the three-dimensional NDP-ACMs (3D-NDP-ACMs). Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being pre-dispersed into a tubular level of dispersions, were used as the starting material and the 3D-NDP-ACMs were obtained via a template-free process. First, a continuous mesoporous PAN/CNT based 3D monolith was established by using a template-free temperature-induced phase separation (TTPS). Second, a nitrogen-doped 3D-ACM with a surface area of 613.8 m2/g and a pore volume 0.366 cm3/g was obtained. A typical supercapacitor with our 3D-NDP-ACMs as the functioning electrodes gave a specific capacitance stabilized at 216 F/g even after 3000 cycles, demonstrating the advantageous performance of the PAN/CNT based 3D-NDP-ACMs.

Microwave plasma-induced graphene-sheet fibers from waste coffee grounds

Graphene-sheet fiber, a novel structure of graphitic carbon, grew from coffee grounds under the condition of microwave plasma irradiation. The resulting fiber consisted of only few-layer graphene without a hollow structure inside while possessing a large amount of graphene edges and high conductivity. Due to these advantages, graphene-sheet fibers may find applications in electrochemical energy conversion and storage.

Electric Contact Characteristic under Low Load of Silver?Carbon Nanotube Composite Plating Film Corroded Using H2S Gas

We fabricated silver–carbon nanotube (Ag–CNT) composite plating films and prepared samples after a H2S gas corrosion test. After corrosion, although the elastic modulus of Ag film increased 1.9 times, there was no marked difference in the mechanical characteristic of Ag–CNT film. At a low load, for the Ag–CNT film after corrosion, there was no polarity and the contact resistance was low and ohmic, although the contact resistance of Ag film after corrosion was high and polar. Therefore, Ag–CNT film can be considered as a promising material for next-generation electrical contact applications.

Vertical Graphene for Biosensors

Abstract Due to its unique structure and amazing physiochemical properties including high chemical inertness, large specific surface area, and high electric conductivity, graphene, a two-dimensional single sheet of carbon atoms consisting of honeycomb lattices, has attracted great scientific interest in the enormous applications, for example, optical electronics, photovoltaic cells, energy storage, composite materials, filter membranes, and biological engineering, and is regarded as a basic building block for graphitic materials of all other dimensionalities. Recently, another two-dimensional graphitic sheet, vertical graphene (VG), which is typically aligned vertically on a substrate, is attractive for the abovementioned graphene-based applications. The novel vertical orientation and open structures of VGs make it more suitable for sensing biomarkers with high sensitivity and selectivity in complex biological conditions. Until now, VG biosensors have been investigated for detecting diverse biomolecules with or without the modification of metal nanoparticles. More importantly, the plasma technique for the growth and modification of VG is useful but simple tool to optimize the biosensor performance and capabilities. In this chapter, we will simply introduce the synthesis, characteristics, and fundamental properties of VG and carefully discuss the recent studies of VG-based biosensors including electronic and electrochemical biosensors.