Study of Sulfur-Nickel Interactions Using Raman Spectroscopy

Abstract

Ni-YSZ cermet and NiO-YSZ composite are exposed to hydrogen containing different concentrations of H 2 S to identify the phases formed under various conditions using Raman spectroscopy and x-ray diffraction (XRD). For samples exposed to hydrogen containing 100 ppm H 2 S at 727°C for 5 days, XRD analysis was unable to detect any changes but several new vibration modes were detected using Raman spectroscopy. These vibration modes are most likely associated with either the adsorption of H 2 S on the surfaces of these materials or the formation of nickel sulfides, suggesting that Raman spectroscopy could be a powerful tool for in-situ study of sulfur poisoning of SOFC anodes. For NiO-YSZ composite samples exposed to hydrogen containing 10% H 2 S at 950°C for 5 days, all NiO particles were converted to nickel sulfide, and vibration modes of NiS were detected using Raman spectroscopy.