Synthesis of copper promoted high temperature water–gas shift catalysts by oxidation–precipitation

• Catalysts based on Fe3O4–Cr2O3–CuO were prepared directly in the active phase.
• Catalysts prepared by oxidation–precipitation showed higher activity in WGS reaction.
• Addition of Cu improved the catalytic performance and the stability in WGS reaction.

Copper promoted high temperature water–gas shift catalysts were directly synthesized in the active phase (Fe3O4) through an oxidation–precipitation (oxiprecipitation) method, avoiding the usual reduction step used to activate the catalyst in the conventional method based on coprecipitation. They were characterized using X-ray diffraction, X-ray fluorescence, infrared spectroscopy, adsorption–desorption of N2 at 77 K, transmission electron microscopy and temperature programmed reduction. Their catalytic activity was also studied. The results indicated that the materials obtained through this new synthesis method exhibited higher catalytic activity than the commercialized catalysts. Furthermore, the addition of copper improved the catalytic performance of oxiprecipitated Fe–Cr materials, increasing the reducibility of the sample and its stability under reaction conditions.