Solvothermal synthesis of porous FeO_x-CeO_2-y composite spheres with high mixing homogeneity

FeOx-CeO2-y composites with different homogeneities were synthesized by the solvothermal method, co-precipitation, and physical mixing. FeOx and CeO2-y in the composites synthesized by the solvothermal method and co-precipitation were homogeneously mixed at the nanometer scale, but physical mixing afforded heterogeneously agglomerated composites. The effects of the homogeneity of the composites were evaluated by probe reverse water-gas shift (RWGS) reaction. The improved homogeneity of FeOx and CeO2-y in the composites resulted in higher catalytic activity, product selectivity, and long-term stability in the RWGS reaction at 700 degrees C. The redox behavior of FeOx was enhanced by finely combined CeO2-y in the case of solvothermally prepared FeOx-CeO2-y, which exhibited excellent crystal structure stability. This study demonstrates the advantages of using the solvothermal method in obtaining homogeneous composites containing multiple metal oxides.