Preparation of nanocrystalline metal (Cr, Al, Mn, Ce, Ni, Co and Cu) modified ferrite catalysts for the high temperature water gas shift reaction

• Cr-free iron based catalysts were evaluated in HTS reaction.
• Promoters affected the structural properties of the iron based catalysts.
• Fe–Al–Cu catalyst (Fe/Al = 10, Fe/Cu = 10) showed the highest activity.
• Fe–Al–Cu catalyst presented higher activity compared to commercial Fe–Cr catalyst.

Water gas shift reaction is an essential process of hydrogen production and carbon monoxide removal from syngas. Fe–Cr–Cu catalysts are typical industrial catalysts for high temperature water gas shift reaction but have environmental and safety concerns related to chromium content. In this work nanocrystalline metal (M)-modified ferrite catalysts (M = Cr, Al, Mn, Ce, Ni, Co and Cu) for replacement of chromium were prepared by coprecipitation method and the effects of promoters on the structural and catalytic properties of the iron based catalysts were studied. Prepared catalysts were characterized using X-ray diffraction (XRD), N2 adsorption (BET), temperature-programmed reduction (TPR) and transmission electron microscopies (TEM) techniques. Temperature-programmed reduction measurements inferred that copper favors the active phase formation and significantly decreased the reduction temperature of hematite to magnetite. In addition, water gas shift activity results revealed that Fe–Al–Cu catalyst with Fe/Al = 10 and Fe/Cu = 5 weight ratios showed the highest catalytic activity among the prepared catalysts. Moreover, the effect of calcination temperature, GHSV and steam/gas ratio on the catalytic performance of this catalyst was investigated.