Sol-gel construction of honeycomb-like CuMn2O4 spinels with high infrared emissivity

Abstract

Spinel materials are gradually becoming high infrared radiation materials with the most potential because of their special crystal structure. However, it is still difficult to design the microstructure reasonably and synthesize it at low temperature. In this paper, the honeycomb-like CuMn2O4 spinels were prepared via a facile sol-gel method with a subsequent low-temperature sintering treatment. Therefore, the CMO samples with numerous pores are conducive to improving absorptivity and emissivity. Moreover, the optimum experimental conditions for high infrared emissivity were acquired by detailed investigation of the synthesis parameters including the molar ratio of trimonium citrate to metal ions, the molar ratio of urea to metal ions and the sintering temperature. Under the synergistic effect of internal factors such as, a suitable amount of impurities, abundant oxygen vacancy, small band gap, and good crystallinity, the obtained sample CMO-800 achieved excellent infrared radiation performance. Its infrared emissivity values at the test temperature of 30 °C and 600 °C separately reached 0.801 and 0.965 in the wavelength range of 3–5 μm. More significantly, this work provides significant guidance for the design and preparation of spinel materials with excellent infrared emissivity.