Sol-gel derived composite silica-carbon electrodes exhibit favorable
electrochemical characteristics. The electrodes benefit from the
conductivity and electrochemical advantages of the carbon powder, from the
favorable properties of the ceramic network and from the versatility of the
sol-gel process. Hydrophobie composite electrodes reject water, only their
outermost surface is wetted and they exhibit good signal to background
currents. A comparison of several types of carbon powders reveals that
higher carbon loading and larger surface area electrodes can be attained by
incorporation of dense graphite powder. When high surface area, small size
carbon-black powder is used, a homogeneous distribution of microelectrodes,
separated by insulating modified silica is formed. This ensemble of
microelectrodes increases the sensitivity of the CCEs by more than two
orders of magnitude as compared to glassy carbon electrode and graphite
CCEs.