| dc.description.abstract | Biofuel cells demand three-dimensional, “high” surface area electrodes with “high”
electrical conductivity and structural integrity. The aim of this project is to design and
fabricate porous carbon structures as electrodes for enzyme and microbe
immobilisation in biofuel cells. These electrodes should have homogeneous pore size
distributions, “high” electrical conductivity, “good” mechanical strength and a
suitable surface for enzyme and microbe immobilisation.
Various routes have been introduced to produce porous carbon electrodes with
different ranges of pore sizes. In the case of microbial fuel cells where the pore sizes
need to be in the micrometric ranges, a foaming method was adopted. To develop
porous carbon electrodes with pore sizes in the nanometre ranges, a templating
method was used. Highly ordered hierarchical mesoporous and macroporous carbon
structures were obtained using the templating method. Ultimately, a polymer blend
technique was developed to produce porous carbon electrodes in large-scales. Porous
carbons prepared by this method composed of pores in the micrometric ranges and
nanometre pores on the walls of the electrodes’ structures.
Various methods to improve mechanical strength and electrical conductivity of the
fabricated electrodes were examined. Successive impregnations of the samples in a
resin improved the strength and the conductivity of the samples. Moreover, to
increase the electrical conductivity of the electrodes, catalytic graphitisation was
tested and different graphitic components were produced. The graphitised carbons
exhibited electrical conductivities of up to fifty times larger than those obtained from
the non-graphitised samples. Electrochemical behaviour of the amorphous and the
graphitic carbon electrodes was investigated and it was found that the fabricated
electrodes were electrochemically active. | |
