High temperature water gas shift reaction over promoted iron based catalysts prepared by pyrolysis method

•Cr-free Fe3O4 based catalysts were prepared by simple route for HTS reaction.•Catalysts were prepared by facile pyrolysis route without adding surfactant.•Fe–Mn–Ni catalyst presented higher activity compared to commercial Fe–Cr catalyst.•Mn and Ni were promising promoters to replace chromium in HTS catalysts.

In this work the effects of different promoters (Cr, Al, Mn, Ce, Ni, Co and Cu) on the structural and catalytic properties of Nanocrystalline iron based catalysts for high temperature water gas shift reaction were investigated. The catalysts were prepared in active phase (Fe3O4) via a facile direct synthesis routs without any additive and characterized using X-ray diffraction (XRD), N2 adsorption (BET), temperature-programmed reduction (TPR), transmission and scanning electron microscopies (TEM,SEM) techniques. The obtained results indicated that synergic effect of Mn and Ni promoters can lead to obtain a Cr-free catalyst with high activity. In addition, the effect of Ni content on the structural and catalytic properties of the Fe–Mn–Ni catalysts was investigated. It was found that Fe–Mn–Ni catalyst with Fe/Mn = 10 and Fe/Ni = 5 weight ratios showed the highest catalytic activity among the prepared catalysts and possessed a stable catalytic performance without any decrease during 10 h time on stream. Moreover, the effect of GHSV and steam/gas ratio on the catalytic performance of this catalyst was investigated.

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