Self-assembled porous nano-composite with high catalytic performance by reduction of tetragonal spinel CuFe2O4 Original Research Article

A tetragonal spinel CuFe2O4 reduced in H2 flow at 633 K shows a self-assembled microstructure that exhibits fine dispersion of copper nanoparticles within the porous Fe3O4 matrix and high catalytic performance. Sintering of copper particles was inhibited significantly even after H2 reduction at 873 K when CuFe2O4 was used as a precursor, while it readily occurred for CuO and physically mixed CuO + Fe2O3. The high thermal stability of copper nanoparticles from the CuFe2O4 after H2 reduction is ascribed to the immiscible interaction between copper and iron (or iron oxides). The spinel CuFe2O4 can be regenerated after an intentional sintering treatment (e.g., in H2 at 873 K) by calcinations in air at 1273 K where the activity and the morphology restored completely. We show that metallurgical knowledge is available to tailor microstructure for designing catalysts.