Relationship Between Electron Hopping Capability and Activity of Fe2O3/MxOy (M= Ce, Cr) Based Catalysts for WGS Reaction

In our previous studies, 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/Cr and Fe/Ce were found to be the most active and durable. The present study was aimed to find out the optimum composition between iron and cerium or chromium as dopants of the spinel structures and correlate their activity with the electron hopping capability of Fe2+/Fe3+ redox couple. For this purpose, various Fe/Ce and Fe/Cr catalysts were prepared using ammonia assisted coprecipitation method by varying the composition between iron and cerium/chromium. The prepared catalysts were characterized by using TPR, Raman and Mossbauer spectroscopic techniques and evaluated for WGS reaction at 500 oC and at a stream to CO ratio 3.5 which the conditions used in our membrane reactor.