The Effects of H ₂ S in Anode Methane on Solid Oxide Electrolysis Cells for Hydrogen Production

Introducing methane into the anode of a solid oxide electrolysis cell (SOEC) can substantially reduce the voltage required for hydrogen production, and the presence of H 2 S in the methane will significantly impact the performance of the anodic oxidation. In this study, Ni‐loaded Gd‐doped CeO 2 (Ni–GDC) is prepared via hydrolysis and impregnation methods, which is used as an anode catalyst of an SOEC under the anode atmosphere of methane with H 2 S. The results show that H 2 S can poison the catalytic oxidization and oxygen evolution active sites on Ni–GDC. The high temperature of 850°C and above enables O 2 on the anode to react with H 2 S to reduce the poisoning of active sites. The H 2 S adsorption on methane oxidation active sites reaches equilibrium under the H 2 S content in the methane anode atmosphere over 400 ppmv. The removal of H 2 S results in partial recovery of methane oxidation active sites at the temperatures above 850°C. Sufficient O 2− under high current density at high temperature can accelerate the oxidation of S species on the active sites, improving the resistance to H 2 S.