Fabrication of double-shelled Fe2O3/CeO2 boxes from CeO2-modified Prussian blue and their enhanced performances for CO removal and water treatment

Multiple components and well-defined complex nanostructures may synergistically enhance the performance and application of composite materials. Herein, hierarchical double-shelled Fe2O3/CeO2 microboxes, with the robust Fe2O3 hollow microcubes inside and CeO2 shell outside, were fabricated by a facile wet chemical process, which involved the decoration of Fe4[Fe(CN)6]3 microcubes with CeO2 nanoparticles, followed by the thermal decomposition of this precursor in air. The non-equilibrium heat treatment induced heterogeneous contraction process during the calcination of the Fe4[Fe(CN)6]3/CeO2 precursor in air, which is responsible for the formation of the unique hollow structures. The pre-deposited CeO2 nanoparticles acted as stabilizer for the exterior surface of Fe4[Fe(CN)6]3 cubes, and consequently played a crucial role in the formation of the unique hollow structures. The CeO2 molar concentration of the resultant products could be tailored by simply varying the feeding amount of Ce(NO3)3. As a CO oxidation catalyst, the as-prepared Fe2O3/CeO2 microboxes displayed higher catalytic activity in comparison with both CeO2 particles and Fe2O3 cubes owing to the high specific surface area and the synergetic interaction between Fe2O3 and CeO2. More importantly, the catalytic performance is closely associated with the component ratio between Fe2O3 and CeO2. In addition, the Fe2O3/CeO2 microboxes also exhibited significant adsorption capacity of Congo red, implying their potential application in water treatment.