A study on the activity recovery behavior of noble metal catalysts against sulfur poisoning

Various noble metals (Pt, Rh, Ru, and Pd) were supported on CeO₂ to understand their sulfur-tolerant catalytic activity. The synthesized catalysts were applied to the water-gas shift reaction in the waste-to-hydrogen process with the injection of 500 ppm H₂S. Among the samples, the PtCe catalyst showed the highest sulfur tolerance and recovery of catalytic activity. Considering the catalytic reaction results and physicochemical properties, the sulfur tolerance of the catalyst is affected by oxygen vacancies and redox properties, which are closely related to the interaction between the metal and the CeO₂ support. In addition, the oxygen storage capacity concentration was used as an indicator for classifying the recovered catalyst and the non-recovered catalyst which had been poisoned by sulfur.