Hybrid Sulfur (HyS) cycle, which consists of an electrolysis step and a thermal decomposition one, has been studying as a promising technology for the hydrogen production from water because of its simple and CO₂ emmision-free process. Exploring low-cost electrode materials with good catalytic activity, excellent electrical conductivity and satisfied corrosion resistance are essential for the practical application of the HyS cycle with a high efficiency of the hydrogen production.
Our research group points out that some electronic conductive ceramics, which are Ti-based pyrochlores (A³⁺₂Ti⁴⁺₂O₇, A=lanthanoides) and perovskites (Sr²⁺Ti⁴⁺O₃), might be candidates as the anode substrates with high corrosion resistance. Additionally, it is found that the Pd electroless-deposition on the electronic conductive ceramics is effective for providing the excellent catalytic properties to the anode substrates.
In this paper, the electrochemical properties of Ir, Ta and Nb doped non-stoichiometric Sr_1-xTi_1-yM_yO_3+δ (M=Ir, Ta, Nb) perovskites covered with Pd thin layer (Pd/Sr_1-xTi_1-yM_yO_3+δ) were investigated in a 50 weight% H₂SO₄ solution at an operation temperature of 353K. From the test results, it was revealed that the over-potentials of the Pd/Sr_1-xTi_1-yM_yO_3+δ electrode decreased with increasing A-site deficiency of the substrates, and their limiting current densities were higher than that of Pd plate. The Pd coated Sr_1-xTi_1-yM_yO_3+δ might be available as anode materials of the electrolysis cell.