Cr-free Fe-based metal oxide catalysts for high temperature water gas shift reaction of fuel processor using LPG

The goal of this study was to identify the most suitable chromium-free iron-based catalysts for the HTS (high temperature shift) reaction of a fuel processor using LPG. Hexavalent chromium (Cr⁶⁺) in the commercial HTS catalyst has been regarded as hazardous material. We selected Ni and Co as the substitution for chromium in the Fe-based HTS catalyst and investigated the HTS activities of these Cr-free catalysts at LPG reformate condition. Cr-free Fe-based catalysts which contain Ni, Zn, or Co instead of Cr were prepared by coprecipitation method and the performance of the catalysts in HTS was evaluated under gas mixture conditions (42% H₂, 10% CO, 37% H₂O, 8% CO₂, and 3% CH₄; R (reduction factor): about 1.2) similar to the gases from steam reforming of LPG (100% conversion at steam/carbon ratio = 3), which is higher than R (under 1) of typically studied LNG reformate condition. Among the prepared Cr-free Fe-based catalysts, the 5 wt%-Co/Fe/20 wt%-Ni and 5 wt%-Zn/Fe/20 wt%-Ni catalysts showed good catalytic activity under this reaction condition simulating LPG reformate gas.