Ce–Mn mixed oxides as supports of copper- and nickel-based catalysts for water–gas shift reaction

•Catalytic activity of pure ceria and manganese oxide improved in Ce–Mn mixed oxides.•Enhanced activity of Cu or Ni catalysts supported on Ce–Mn mixed oxides with respect to bare supports.•Ni catalysts capable of adjusting the CO concentration of a typical WGS reactor inlet stream to the requirements of a PAFC.

Cerium-manganese mixed oxides with different composition were prepared by co-precipitation, characterized and evaluated for the water–gas shift (WGS) reaction. Base metal (5 wt.% Cu and 5 wt.% Ni) catalysts supported on Ce–Mn mixed oxides were also tested for the WGS reaction. The activity of the bare supports is higher in the mixed samples than in pure ceria or manganese oxide. This result can be explained by a combination of greater reducibility and surface area in the mixed samples. Addition of base metals produces superior WGS catalysts. Particularly, nickel catalysts tested are able to reduce typical CO concentrations entering the WGS process to the CO levels tolerated by phosphoric acid fuel cells in a single unit operated at 400 °C.