Keywords Catalysts · Dendrimers · Nanoparticles · Oxidation · Supramolecular
chemistry
Abbreviations
AAC
Alkyne-azide cycloaddition
CNT
Carbon nanotube
DEN
Dendrimer-encapsulated nanoparticles
DPA
Dendritic poly(phenylazomethine)
DSN
Dendrimer-stabilized nanoparticles
EDS
Energy-dispersive X-ray spectroscopy
EWG
Electron-withdrawing groups
GCE
Glassy carbon electrodes
GMC
Graphitized mesoporous carbon
NCD
Nanoparticle-cored dendrimers
NPs
Nanoparticles
ORR
Oxygen reduction reaction
PAMAM Poly(amidoamine)
PPI
Poly(propyleneimine)
PyTPM
Pyridoxine(triphenylene)methane
STEM
Scanning transmission electron microscope
TEG
Triethylene glycol
TOF
Turnover frequency
TON
Turnover number
TPM
Tetraphenylmethane
1 Introduction
The advanced science and technology of catalysis is particularly important for
overcoming the economic and environmental issues in our present society. Research
in the 1990s, which revealed the surprising activity of Au nanoparticles (NPs),
largely investigated novel catalytic materials on the nanoscale with properties
different from their bulk counterparts [1]. Nanotechnology has since fascinated
many researchers in fields of science such as catalysis, organic chemistry, surface
science, molecular biology, semiconductor physics, etc. Interesting catalytic features
of NPs have been revealed year by year, so that the number of publications on
catalysis using NPs has exponentially increased.
The NPs used in catalysis have been synthesized with thermodynamic stability as
a driving force, i.e., the particles are surrounded by organic ligands such as thiols,
amines, carbonyls, or solvent molecules. These stabilized particles normally show
low catalytic performance, because dissociation of the ligands takes place to generate the reactive surface sites. In contrast, metastable NPs and clusters composed of a
132
M. Tanabe and K. Yamamoto
chemistry
Abbreviations
AAC
Alkyne-azide cycloaddition
CNT
Carbon nanotube
DEN
Dendrimer-encapsulated nanoparticles
DPA
Dendritic poly(phenylazomethine)
DSN
Dendrimer-stabilized nanoparticles
EDS
Energy-dispersive X-ray spectroscopy
EWG
Electron-withdrawing groups
GCE
Glassy carbon electrodes
GMC
Graphitized mesoporous carbon
NCD
Nanoparticle-cored dendrimers
NPs
Nanoparticles
ORR
Oxygen reduction reaction
PAMAM Poly(amidoamine)
PPI
Poly(propyleneimine)
PyTPM
Pyridoxine(triphenylene)methane
STEM
Scanning transmission electron microscope
TEG
Triethylene glycol
TOF
Turnover frequency
TON
Turnover number
TPM
Tetraphenylmethane
1 Introduction
The advanced science and technology of catalysis is particularly important for
overcoming the economic and environmental issues in our present society. Research
in the 1990s, which revealed the surprising activity of Au nanoparticles (NPs),
largely investigated novel catalytic materials on the nanoscale with properties
different from their bulk counterparts [1]. Nanotechnology has since fascinated
many researchers in fields of science such as catalysis, organic chemistry, surface
science, molecular biology, semiconductor physics, etc. Interesting catalytic features
of NPs have been revealed year by year, so that the number of publications on
catalysis using NPs has exponentially increased.
The NPs used in catalysis have been synthesized with thermodynamic stability as
a driving force, i.e., the particles are surrounded by organic ligands such as thiols,
amines, carbonyls, or solvent molecules. These stabilized particles normally show
low catalytic performance, because dissociation of the ligands takes place to generate the reactive surface sites. In contrast, metastable NPs and clusters composed of a
132
M. Tanabe and K. Yamamoto