(197c) Cr and Ce Doped Fe/Ce Catalysts for High Temperature Water Gas Shift Reaction

Utilizing water gas shift (WGS) membrane reactors to produce high purity hydrogen is a great way to solve serious energy problems in the future. In our previous studies we introduced a variety of metal ions (M = Cr, Co, Zr, Hf, and Mo) into Fe/Ce (spinel lattice) and screened for effectiveness for a high-temperature WGS reaction. The idea was to stimulate the ferrite formation via doping with certain foreign cations and to promote the electron hopping capability of Fe³⁺ « Fe²⁺ redox couple. Among the various catalysts Fe/Ce/Cr and Fe/Ce/Co catalysts exhibit better activity. The WGS feed condition were chosen to mimic conditions found in a membrane reactor for industrial applications. In the present study we aim to find the optimum amount of Cr and Co dopant that can be incorporated into the hematite lattice to promote maximum WGS activity. For this purpose, various Fe/Ce/Cr and Fe/Ce/Co catalysts were prepared by ammonia assisted coprecipitation method with variable Fe//Ce/M (M= Cr, and Co) atomic ratios. The chosen atomic ratios for the Fe/Cr catalysts are 10:0.5, 10:1, 10:1.5, and 10:2. The prepared catalysts were characterized by using TPR, Raman, Mossbauer, and X-ray photo electron spectroscopic techniques and evaluated for WGS reaction in the temperature region 400-550 ^oC and at a stream to CO ratio of 3.5 and 1.5. Interestingly, our shift activity findings reveal that among the various catalysts Fe/Ce/Co (10:1:1.5) catalyst exhibits optimum performance. These results will be discussed in the presentation.