Carbon dioxide decomposition using SrFeCo_0.5O_x, a nonperovskite-type metal oxide

Greenhouse gas emission reductions need to be realized urgently to mitigate climate change. The most realistic solution is to store carbon dioxide (CO₂) underground; however, this approach suffers from several problems such as leaks and contaminations are susceptible to earthquakes and have high cost. Therefore, many researchers are actively studying CO₂ decomposition or utilization instead of storage. Such studies aim to decompose CO₂ into useful materials. Although metal oxides of previous studies decomposed CO₂ completely into carbon (C) at ∼300»°C, these results were obtained only in a laboratory-scale batch-type reactor. For practical applications, decomposition of a continuous flow of CO₂ needs to be achieved. In this report, we demonstrate CO₂ decomposition using metal oxide catalysts such as spinel-type Ni-ferrites and Sr/Fe-based nonperovskites. Based on the suggested reaction mechanism, catalysts were selected and tested in a continuous CO₂ decomposition reactor. CO₂ decomposition of up to ∼90% was achieved, and decomposition of ≥80% lasted for more than one hour at moderate temperatures. Because SrFeCo_0.5O_x catalyst selected based on a theoretical mechanism shows high decomposition and good reproducibility, it is anticipated that these results contribute to GHG emission reduction.