Modifying La_0.6Sr_0.4MnO₃ Perovskites with Cr Incorporation for Fast Isothermal CO₂-Splitting Kinetics in Solar-Driven Thermochemical Cycles

Perovskites are promising oxygen carriers for solar-driven thermochemical fuel production due to higher oxygen exchange capacity. Despite their higher fuel yield capacity, La_0.6Sr_0.4MnO₃ perovskite materials present slow CO₂-splitting kinetics compared with state-of-the-art CeO₂. In order to improve the CO production rates, the incorporation of Cr in La_0.6Sr_0.4MnO₃ is explored based on thermodynamic calculations that suggest an enhanced driving force toward CO₂ splitting at high temperatures for La_0.6Sr_0.4Cr_xMn_1−xO₃ perovskites. Here, reported is a threefold faster CO fuel production for La_0.6Sr_0.4Cr_0.85Mn_0.15O₃ compared to conventional La_0.6Sr_0.4MnO₃, and twofold faster than CeO₂ under isothermal redox cycling at 1400 °C, and high stability upon long-term cycling without any evidence of microstructural degradation. The findings suggest that with the proper design in terms of transition metal ion doping, it is possible to adjust perovskite compositions and reactor conditions for improved solar-to-fuel thermochemical production under nonconventional solar-driven thermochemical cycling schemes such as the here presented near isothermal operation.