Surface electric conductivity in wet porous silica ceramics

Full text: To elaborate the best material for fuel cell electrodes is still actually. Gamma-irradiation of highly porous alumina-silica glasses at 77 K was found earlier by us (E-MRS 2003 Spring Meeting) to enhance the proton conductivity with the peak at 280 K. Protons were produced from water radiolysis proportional to the gamma-flux. The surface conductivity of wet porous silica ceramics has the peak at 307 K, which is absent in dry samples and hence is due to proton transport. The activation energy = 0.6 eV and frequency factor = 2.5·107 Hz were calculated from the experimental temperature dependence's of the surface conductivity and both decreased after gamma-irradiation significantly. The hydrogen bond network seems to form effectively on the highly developed silica surface with the gamma-irradiation induced surface radicals. The work is supported by the grant F2.1.2 from Center of Science and Technology of Uzbekistan