Solvothermal synthesis of porous FeOx–CeO2−y composite spheres with high mixing homogeneity

Abstract

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 °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.