Outstanding photothermal performance of metal-like CeO2–Co3O4 and excellent photothermal storage of Ca(OH)2–CeO2–Co3O4.

[Display omitted] • A redox system has high density of delocalized charge carrier. • Metal-like CeO 2 –Co 3 O 4 absorbs light strongly in full solar spectrum. • CeO 2 –Co 3 O 4 can catalyze Ca(OH) 2 dehydration. • Ca(OH) 2 –CeO 2 –Co 3 O 4 composite can efficiently absorb sun light. • Ca(OH) 2 –CeO 2 –Co 3 O 4 is promising for direct photothermal storage. Thermal energy storage technology is an effective means for expanding the use of solar energy. Light harvesting across the full solar wavelength is essential for ensuring photothermal efficiency. Lattice defect engineering has been widely used to narrow the band gap and induce surface plasmon resonance absorption. In this study, we present an alternate method for intensifying light absorption. The CeO 2 –Co 3 O 4 redox system possesses highly delocalised electrons and numerous oxygen vacancies, allowing considerable light harvesting over the full solar spectrum. By incorporating CeO 2 –Co 3 O 4 as an absorber, the photothermal temperature, photothermal dehydration conversion and reversibility of the thermal storage and release cycles of Ca(OH) 2 can be drastically enhanced. The dehydration kinetics of Ca(OH) 2 are also substantially increased by reducing the dehydration activation energy using CeO 2 –Co 3 O 4. The Ca(OH) 2 –CeO 2 –Co 3 O 4 composite is a promising candidate for one-step photothermal conversion and thermal energy storage. Herein, we develop a light–material design for the very first time using a redox system. [ABSTRACT FROM AUTHOR]