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

Abstract

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 1Àx Mn x O 3Àd (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 3Àd is designed as the active protective coating of a lab-scale receiver, which has a thermal capacity of 82.95 kJ kg À1 . The smart coating can slow down the temperature rising rate from 8.5 C min À1 to 3 C min À1 in the first 2 min under strong solar radiation, effectively relieving the thermal shock of the receiver.

Recent Status and Developments of Vacancies Modulation in the ABO3 Perovskites for Catalytic Applications

“…(b) Thermochemical protective coating for molten salt receivers. Reproduced with permission [59] . Copyright 2021, CC BY‐NC‐ND license.…”

“…Interestingly, the regulated thermochemical redox temperature via Vo modulation could also be applied for protecting solar molten salt receivers. As shown in Figure 10b, an active coating was developed to guard molten salt receivers [59] . The Vo‐enriched BaCo 1−x Mn x O 3−δ (x=0–0.4) was designed as solar molten salt receiver with adjustable temperature (426‐702 °C), much lower than that of other metal oxides (530‐850 °C).…”

“…As shown in Figure 10b, an active coating was developed to guard molten salt receivers. [59] The Vo-enriched BaCo 1À x Mn x O 3À δ (x = 0-0.4) was designed as solar molten salt receiver with adjustable temperature (426-702 °C), much lower than that of other metal oxides (530-850 °C). Interestingly, to increase the formation energy of Vo could raise redox temperature.…”

“…Reproduced with permission. [59] Copyright 2021, CC BY-NC-ND license. (c) Schematic diagram of ABO 3 as acetone and dynamic response of pure LFO and LF 1À x P x O 3À δ (x = 0.005-0.05) sensors at different condition.…”

Active Thermochemical Barrier Coatings Using Metal Oxides: First Experimental Results

“…17 thermal coating can alleviate the initial thermal shock but no direct experimental evidence of the thermochemical reaction was provided. 17 For TBCs working at higher at higher temperatures, the cobalt oxide system (Co 3 O 4 /CoO) is a potential candidate, due to its high theoretical enthalpy (844 kJ/kg) and good kinetics. 21−28 In a previous work, the production of Co-based oxide thin films was deeply investigated.…”