Performance of Iron-Based Perovskite-type Oxides for Chemical Looping Dry Reforming of Methane

Partial oxidation of methane has emerged as a promising approach for the effective utilization of methane. When combined with the thermochemical CO2 reduction through the "chemical looping" concept, it can realize the coproduction of syngas and high-purity carbon monoxide. In this study, we proposed a chemical looping dry reforming of methane (CL-DRM) process by using iron-based perovskite-type oxides as oxygen carriers (OCs). This process has the potential to efficiently utilize low-grade solar heat and convert it into high-grade chemical energy. To identify efficient perovskite-type OCs, we synthesized and characterized LaFeO3, SrFeO3, La0.5Sr0.5FeO3, SrFe0.5Ni0.5O3, and LaFe0.5Ni0.5O3. The candidates were evaluated via H-2/CH4 temperature-programmed reduction and isothermal chemical looping redox cycles within the temperature range of 750-950 degrees C, revealing their potential for integration into the CL-DRM system. A series of characterization tests were tested to unveil the reaction mechanism for different iron-based perovskites. The results demonstrate that the introduction of nickel substitution enhances the activity of the iron-based perovskites, and lanthanum proves to be the more suitable A-site element for these materials. Among the candidates, LaFeO3 shows the highest performance at 950 degrees C; LaFe0.5Ni0.5O3 exhibits the best reactivity, CO selectivity, and carbon resistance at 750 and 850 degrees C. Our study is expected to facilitate the development of efficient and clean methane conversion, while simultaneously advancing solar thermochemical fuel production and CO2 utilization.