Thermochemical splitting of CO2 on perovskites for CO production: A review

Energy supply dominated by fossil energy has been and remains the main cause of carbon dioxide emissions, the major greenhouse gas leading to the current grave climate change challenges. Many technical pathways have been proposed to address the challenges. Carbon capture and utilization (CCU) represents one of the approaches and thermochemical CO2 splitting driven by thermal energy is a subset of the CCU, which converts the captured CO2 into CO and makes it possible to achieve closed-loop carbon recirculation. Redox-active catalysts are among the most critical components of the thermochemical splitting cycles and perovskites are regarded as the most promising catalysts. Here we review the latest advancements in thermochemical cycles based on perovskites, covering thermodynamic principles, material modifications, reaction kinetics, oxygen pressure control, circular strategies, and demonstrations to provide a comprehensive overview of the topical area. Thermochemical cycles based on such materials require the consideration of trade-off between cost and efficiency, which is related to actual material used, operation mode, oxygen removal, and heat recovery. Lots of efforts have been made towards improving reaction rates, conversion efficiency and cycling stability, materials related research has been lacking – a key aspect affecting the performance across all above aspects. Double perovskites and composite perovskites arise recently as a potentially promising addition to material candidates. For such materials, more effective oxygen removal would be needed to enhance the overall efficiency, for which thermochemical or electrochemical oxygen pumps could contribute to efficient oxygen removal as well as serve as means for inert gas regeneration. The integration of thermochemical CO2 splitting process with downstream fuel production and other processes could reduce costs and increase efficiency of the technology. This represents one of the directions for the future research.