Regulating thermochemical redox temperature via oxygen defect engineering for protection of solar molten salt receivers

An active coating based on thermochemical redox reactions is proposed to protect molten salt receivers from solar flux fluctuation. However, appropriate metal oxides working in the temperature range of 530 and 850°C are still missing. Herein, we put forward an oxygen defect engineering strategy to regulate the thermochemical redox temperatures of perovskites. A tunable temperature range of 426–702°C is obtained by BaCo(1−x)Mn(x)O(3−δ) (x = 0–0.4). It is found that a raised redox temperature can be obtained with the increase of the oxygen vacancy formation energy. For application, BaCo(0.8)Mn(0.2)O(3−δ) is designed as the active protective coating of a lab-scale receiver, which has a thermal capacity of 82.95 kJ kg(−1). The smart coating can slow down the temperature rising rate from 8.5°C min(−1) to 3°C min(−1) in the first 2 min under strong solar radiation, effectively relieving the thermal shock of the receiver.