2006 年 31 巻 2 号 p. 32-41
Sulfur-based hybrid cycle (SHC) process has been attracted much attention as a mass production process of hydrogen, which consists of an electrolysis step, 2H2O + SO2 H2 + H2SO4 (353 K), and a thermal decomposition step, H2SO4 H2O + SO2 + 1/2O2 (1123 K). To achieve high efficiency for hydrogen evolution, a development of the electrode materials with high corrosion resistance, high electrical conductivity and low anodic over-potential is a key technology for the electrolysis in H2SO4 solutions.
We found that some kinds of A-site deficient Ti-based pyrochlores (A3+2Ti4+2O7) showed high corrosion resistance in a 50 wt% H2SO4 solution at the oper ating temperature. Also, it was revealed that the electronic conductive ceramics had good electrical conductivity of 1 S/cm.
In this paper, we measured the electrical conductivity and corrosion resistance of perovskites (A2+Ti4+O3), such as Gd2-xTi2O7-δ and Sr1-xTi1-yNbyO3+δ, in a 50 wt% H2SO4 solution at the operating temperature, and tried to coat Pd particles on the electronic conductive ceramics by electroless deposition technique in order to apply some catalytic property to the ceramics and measured the electrochemical properties of the Pd-coated electronic conductive ceramics.
