Earth abundant perovskite oxides for low temperature CO2 conversion

Abstract

Conversion of CO₂ in a scalable technology has the potential for enormous energy and environmental impact but remains a challenge. We present several stable, earth abundant perovskite oxide materials for the reverse water gas shift chemical looping (RWGS-CL) process as a potential solution for this CO₂ mitigation problem. This material and process combination circumvents issues plaguing other emerging technologies, viz. poor rates of CO₂ conversion, high operation temperatures, use of precious metal catalysts, or combinations thereof. Using DFT-calculated oxygen vacancy formation energy, a key descriptor for the RWGS-CL process, we have successfully predicted several earth abundant perovskite oxides with high CO₂ conversion capability. We simultaneously achieved 100% selective CO generation from CO₂ at the highest known rates (∼160 μmoles per min per gram perovskite oxide) at record low process temperatures of 450–500 °C using lanthanum and calcium based perovskite oxides. These materials are stable over several RWGS-CL cycles, enabling industrial implementation.