Toshiaki Enoki

General equation for the determination of the crystallite size La of nanographite by Raman spectroscopy

This work presents a systematic study of the ratio between the integrated intensities of the disorder-induced D and G Raman bands (ID∕IG) in nanographite samples with different crystallite sizes (La) and using different excitation laser energies. The crystallite size La of the nanographite samples was obtained both by x-ray diffraction using synchrotron radiation and directly from scanning tunneling microscopy images. A general equation for the determination of La using any laser energy in the visible range is obtained. Moreover, it is shown that ID∕IG is inversely proportional to the fourth power of the laser energy used in the experiment.

Observation of zigzag and armchair edges of graphite using scanning tunneling microscopy and spectroscopy

The presence of structure-dependent edge states of graphite is revealed by both ambient and ultrahigh-vacuum (UHV) scanning tunneling microscopy and scanning tunneling spectroscopy observations. On a hydrogenated zigzag (armchair) edge, bright spots are (are not) observed together with a

Probing the catalytic activity of porous graphene oxide and the origin of this behaviour

(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R30\ifmmode^\circ\else\textdegree\fi{}

Edge state on hydrogen-terminated graphite edges investigated by scanning tunneling microscopy

superlattice near the Fermi level (

Experimental evidence of a single nano-graphene

{V}_{S}\ensuremath{\sim}\ensuremath{-}30\phantom{\rule{0.3em}{0ex}}\mathrm{mV}

Electronic structures of graphene edges and nanographene

for a peak of the local density of states) under UHV, demonstrating that a zigzag edge is responsible for the edge states, although there is no appreciable difference between as-prepared zigzag and armchair edges in air. Even in the hydrogenated armchair edge, however, bright spots are observed at defect points, at which partial zigzag edges are created in the armchair edge.

Two-dimensionality and suppression of metal-semiconductor transition in a new organic metal with alkylthio substituted TTF and perchlorate

Graphene oxide, a two-dimensional aromatic scaffold decorated by oxygen-containing functional groups, possesses rich chemical properties and may present a green alternative to precious metal catalysts. Graphene oxide-based carbocatalysis has recently been demonstrated for aerobic oxidative reactions. However, its widespread application is hindered by the need for high catalyst loadings. Here we report a simple chemical treatment that can create and enlarge the defects in graphene oxide and impart on it enhanced catalytic activities for the oxidative coupling of amines to imines (up to 98% yield at 5 wt% catalyst loading, under solvent-free, open-air conditions). This study examines the origin of the enhanced catalytic activity, which can be linked to the synergistic effect of carboxylic acid groups and unpaired electrons at the edge defects. The discovery of a simple chemical processing step to synthesize highly active graphene oxide allows the premise of industrial-scale carbocatalysis to be explored.

Electronic states of graphene nanoribbons and analytical solutions

The edge states that emerge at hydrogen-terminated zigzag edges embedded in dominant armchair edges of graphite are carefully investigated by ultrahigh-vacuum scanning tunneling microscopy (STM) measurements. The edge states at the zigzag edges have different spatial distributions dependent on the

Cutting of Oxidized Graphene into Nanosized Pieces

\ensuremath{\alpha}

Spin-crossover behaviour of the coordination polymer FeII(C5H5N)2NiII(CN)4

- or