(683f) Sulfur Tolerant Doped Fe/Ce Catalysts for the High Temperature Water Gas Shift Reaction – TPR and Mossbauer Spectroscopic Study
To stabilize the formation of Magnetite phase during the activation and to promote the Fe3+ ↔ Fe2+ redox couple during the water gas shift reaction, in our previous study we introduced a variety of metal ions (M = Cr, Mn, Co, Ni, Cu, Zn, and Ce) into iron oxide (spinel lattice) and screened for effectiveness for a high-temperature water?gas shift reaction. Among the various catalysts tested Fe/Ce and Fe/Cr spinels with an atomic ratio of 10:1 exhibited the highest activity. Between the Fe/Ce and Fe/Cr catalysts, Fe/Ce catalyst exhibits stable and higher activity in the presence of sulfur compared to Fe/Cr catalysts. In the present study, we investigated the effect of foreign metals as a dopant on high temperature water gas shift activity of Fe/Ce catalyst. For this purpose, various metals like Co, Mo, Zr, Hf, and Cr were doped into Fe/Ce catalyst by using ammonia assisted coprecipitation method. The prepared catalysts were characterized by using TPR, Raman Mossbauer spectroscopic techniques and evaluated for WGS reaction in the temperature region of 400-550 oC and at a steam to CO ratio of 1, which the conditions typically used in our membrane reactor. A relatively high space velocity 60,000 h-1 was used in this study. To verify the sulfur tolerance the experiments were also carried out in the presence of H2S. These interesting results will be presented in the presentation.