20
Electrochemistry with Nanoparticles
S. Devarajan and S. Sampath
Outline
This chapter is organized into sections corresponding to various electrochemical
characteristics of nanometallic particles. The introduction gives a brief idea of
the basics of colloids together with related literature. Subsequently, the electrochemistry with nanoparticles and ensembles of nanoelectrodes is explained followed by the electrochemical coulomb staircase behaviour of monolayer-protected
nanometallic clusters. The investigation of nanoparticles using techniques based
on combinations of different spectroscopic and electrochemical techniques is then
reviewed. Sensors and electrocatalysis form the next sections and finally a summary and perspectives are given.
20.1
Introduction
Small metallic particles have been the subject of scientific and technological interest since the time of Faraday when he proposed that the ruby red color of gold
colloid is the consequence of its small particle size [1]. A large number of theoretical and experimental studies have been carried out to understand the basic characteristics of the optical, electronic, chemical and mechanical properties of metallic
nanoparticles [2–17]. Mie has made seminal contributions to quantitatively correlate the changes in the optical properties with the variation in the size of the particles [2]. The size-dependent properties have given rise to enormous applications
that have emerged in the last few decades. Data storage, sensing devices, catalysis,
biological interfaces, quantum level phenomena, nanoelectromechanical devices
and nanotribology are some of the areas where the impact has already been very
substantial.
Electrochemistry has been inherently associated with nanoscience, particularly
when the stability and the assembly of the particles are probed using the so-called
‘bottom up’ chemical approach. The stability of colloids is related to the repulsive
forces when the double layers around them overlap with each other. Low electrolyte
646
Electrochemistry with Nanoparticles
S. Devarajan and S. Sampath
Outline
This chapter is organized into sections corresponding to various electrochemical
characteristics of nanometallic particles. The introduction gives a brief idea of
the basics of colloids together with related literature. Subsequently, the electrochemistry with nanoparticles and ensembles of nanoelectrodes is explained followed by the electrochemical coulomb staircase behaviour of monolayer-protected
nanometallic clusters. The investigation of nanoparticles using techniques based
on combinations of different spectroscopic and electrochemical techniques is then
reviewed. Sensors and electrocatalysis form the next sections and finally a summary and perspectives are given.
20.1
Introduction
Small metallic particles have been the subject of scientific and technological interest since the time of Faraday when he proposed that the ruby red color of gold
colloid is the consequence of its small particle size [1]. A large number of theoretical and experimental studies have been carried out to understand the basic characteristics of the optical, electronic, chemical and mechanical properties of metallic
nanoparticles [2–17]. Mie has made seminal contributions to quantitatively correlate the changes in the optical properties with the variation in the size of the particles [2]. The size-dependent properties have given rise to enormous applications
that have emerged in the last few decades. Data storage, sensing devices, catalysis,
biological interfaces, quantum level phenomena, nanoelectromechanical devices
and nanotribology are some of the areas where the impact has already been very
substantial.
Electrochemistry has been inherently associated with nanoscience, particularly
when the stability and the assembly of the particles are probed using the so-called
‘bottom up’ chemical approach. The stability of colloids is related to the repulsive
forces when the double layers around them overlap with each other. Low electrolyte
646