Tailored SrFeO3-δ for chemical looping dry reforming of methane

Abstract

Chemical looping dry reforming of methane (CL-DRM) is a highly efficient process that converts two major greenhouse gases (CH₄ and CO₂) into syngas ready for the feedstock of liquid fuel production. One of the major obstacles facing this technology now is creating oxygen carriers that are stable and reactive. We fabricated high-performance Sr_0.98Fe_0.7Co_0.3O_3-δ perovskite-structured oxygen carrier by combining A-site defects and B-site doping of SrFeO_3-δ. During isothermal CL-DRM tests at 850 °C, Sr_0.98Fe_0.7Co_0.3O_3-δ achieved 87% CH₄ conversion and 94% CO selectivity in the CH₄ partial oxidation reaction, followed by a syngas yield of 8.5 mmol/g, and CO yield of 4.2 mmol/g in CO₂ decomposition. A-site defect engineering of the perovskite creates abundant oxygen vacancies and enhances oxygen storage capacity (OSC). Co-doping of the B-site of Sr_0.98FeO_3-δ increases oxygen mobility and CH₄/CO₂ activation, resulting in high activity in the CL-DRM process. This methodology resulted in high ionic mobility and facilitated the rapid diffusion of oxygen in the bulk phase, thereby increasing the redox properties of SrFeO_3-δ. The oxygen carrier exhibits excellent structural stability and regeneration ability in successive redox cycles. This strategy offers a simple but very effective pathway to tailor OSC, oxygen mobility, and oxygen vacancies of perovskite-structured materials for chemical looping or redox-involved processes.