Cobalt-Based Perovskites as Efficient Oxygen Exchange Redox Materials for Solar Thermochemical Application

Solar thermochemical CO2 splitting (STCS) cycles provide the promising routes to generate renewable fuel, fuel precursors, or chemical feedstocks by the utilization of renewable resources like solar thermal energy and CO2 relating to current energy as well as climate change. Perovskites have been proposed as the potential oxygen exchange redox materials for the two-step STCS process due to their greater oxygen release and redox stability. Herein, the oxygen release and redox stability were investigated for the cobalt-based perovskites (SrCoO3-δ and SrCo0.9Zr0.1O3-δ) as the potential STCS candidates. Consequently, the XRD, FT-IR, and Raman confirmed the dual-phase perovskite constitutions of SrCo0.9Zr0.1O3-δ (i.e. SrCoO2.29 and SrZrO3) compared to SrCoO3-δ. The thermogravimetric analysis indicated the incorporation of Zr could facilitate the oxygen release and enhance the phase stability. The near-equilibrium lattice oxygen release and uptake at high temperatures could be observed through the redox performance of SrCo0.9Zr0.1O3-δ at different heating and cooling rates. The results are noteworthy and demonstrate the potential of Zr-enhanced cobalt-based perovskites as the oxygen exchange redox materials for practical solar thermochemical applications.