Remarkable solar thermochemical CO2 splitting performances based on Ce- and Al-doped SrMnO3 perovskites

Abstract

Solar thermochemical CO₂ splitting has emerged as a promising strategy for solar fuel production to alleviate climate change challenges and reduce the energy crisis. However, traditional redox materials still suffer from low CO production, poor cycle stability, high operating temperature, and large temperature swing, leading to low solar-to-fuel efficiency. Herein, Ce- and Al-doped SrMnO₃ perovskites are proposed for high-performance solar thermochemical CO₂ splitting within moderate temperature swing (1350/1100 °C). Sr_0.6Ce_0.4Mn_0.8Al_0.2O₃ demonstrates a remarkable CO yield of 799.34 μmol g⁻¹, which is ∼6.67 times as high as that of benchmark CeO₂. Fast CO₂ splitting kinetics of SCMA20 is demonstrated by the CO peak production rate enhanced by 142% compared with undoped SrMnO₃. The proposed Sr_0.6Ce_0.4Mn_0.8Al_0.2O₃ also exhibits excellent stability with no obvious deactivation or degradation over multiple cycles. The ultrahigh CO yield can be attributed to lower oxygen vacancy formation (3.65 eV) and migration energy (2.14 eV) as confirmed by DFT calculations, and the transformation of the first-order reaction (F1) to the second-order reaction (F2) compared to SrMnO₃. This work provides a new path for high-performance solar thermochemical CO₂ splitting with high CO production, fast reaction kinetics, good cycling stability, moderate temperature swing, and high solar absorptance.