High-entropy perovskite oxides for direct solar-driven thermochemical CO₂ splitting

The global energy crisis and climate change have fueled interest in solar-driven thermochemical CO₂ splitting as a potential solution. However, conventional materials like CeO₂ encounter limitations attributable to their low solar absorptivity and CO yield (even at high reduction temperatures), exerting a detrimental influence on both solar energy utilization and process efficiency. This study proposes high-entropy A-site doped perovskites as a potential solution for efficient solar thermochemical CO₂ splitting. The increased configurational entropy enhances the solar thermal CO₂ splitting cycles by decreasing oxygen vacancy formation energy and lattice oxygen migration energy barrier. This is supported by experimental results, where Sm_0.25Sr_0.25Ca_0.25La_0.25MnO₃ achieved a maximum CO yield of 764.76 μmol g⁻¹ with low temperature difference between the reduction and oxidation steps, marking an important progress in solar thermal CO₂ splitting cycles. The study demonstrates the potential of high-entropy perovskites for direct solar energy harvesting with high spectrum absorption coefficients and sustainable CO₂ utilization.