Enhanced infrared radiation properties of CoFe2O4 by single Ce3+-doping with energy-efficient preparation

Spinel ferrites were recently explored as an infrared radiance materials to provide an environmental friendly energy candidate for industrial heating and drying. Ce3+ was selected to dope cobalt ferrites, forming CoFe2−xCexO4 (x=0, 0.01, 0.05, 0.1 and 0.15) via the sol–gel auto-combustion method to enhance the infrared radiation properties. The samples were characterized by use of FTIR, TG/DSC, SEM and XRD measurements. The infrared radiation properties quantified by infrared emissivity was examined via a Fourier transform infrared spectrometer. The results showed that the Ce3+ content and the sintering temperature were the two crucial factors for regulating the infrared radiation properties of Ce3+-doped cobalt ferrites. An improvement of infrared radiation properties can be achieved from the accelerated lattice strain as well as the stable solid solution structure of single phase (CoFe2O4). The infrared emissivity of the ferrites decreased once the second phase (CeO2) appeared. Doping with small Ce3+ content (x≤0.05) and sintering at temperature no more than 600 °C were found effective for the inhibition of second phase (CeO2) formation. There was a positive correlation between the lattice strain and the infrared emissivity. The highest infrared emissivity (0.92±0.01) was obtained from CoFe1.95Ce0.05O4 sintered at 600 °C for 2 h in which the maximum lattice strain (0.341%) occurred. Cobalt ferrites doping with single Ce3+ have potential for the application of infrared heating and drying field.