Infrared emissivity behavior of doped CeO₂ at high temperature

In this study, cerium dioxide (CeO₂) materials doped with one (Gd³⁺, GDC), two (Gd³⁺ and Na⁺, GNDC), and three (Gd³⁺, Na⁺, and Eu³⁺, EGNDC) components were, respectively, prepared, and their high-temperature infrared emissivity was investigated through experimental measurements and theoretical calculations. The experimental results show that GDC exhibits the highest oxygen vacancy concentration, highest conductivity, and narrowest band gap; furthermore, it exhibits an ultralow infrared emissivity (0.202 at 600 °C). The band structure calculations reveal that the Fermi level of GDC shows the highest total density of states, and electrons are more likely to enter the conduction band, which increases the conductivity and thus reduces the infrared emissivity. Furthermore, the infrared reflectance decreases gradually with increasing number of doping components, and the highest infrared reflectance and lowest infrared emissivity for GDC are obtained at 3–5 μm. These findings are consistent with the experimental results.