Chemical Looping Reforming of Methane Coupled with CO2 Splitting Using a Sol–Gel-Derived LaFe0.4Co0.6O3 Oxygen Carrier

Abstract Chemical looping reforming of CH4 coupled with CO2 splitting (CLRCS) is an attractive technology that enables covalorization of CO2 and CH4 to high- value syngas. In CLRCS, oxygen carriers shuttle oxygen from CO2 to CH4, enabling selective methane partial oxidation and CO2 splitting. However, rational optimization of perovskite oxygen carriers is pivotal to advancing this technology. Herein, a set of Co-doped LaFeO3 perovskite oxygen carriers (LaFe1–xCoxO3, x = 0–1) were synthesized via an optimized sol–gel method. The catalytic performances of materials were measured in a fixed-bed reactor at 750–950 °C, complemented by X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterizations for structural analysis. Among all tested samples, LaFe0.4Co0.6O3 achieves superior performance at 850 °C, with 92% CH4 conversion and ∼90% syngas selectivity (H2/CO ≈ 2). Moderate Co incorporation remodels the Fe-centered perovskite lattice, which appeared to tune the material redox properties. By contrast, excessive Co doping (x > 0.6) deteriorates regeneration capacity and cyclic stability. Catalytic behavior is highly sensitive to the oxidant atmosphere: CO2 and H2O as mild oxidants are hypothesized to preserve the oxygen carrier in a favorable incompletely oxidized state for selective reforming, whereas O2 causes overoxidation, restricting CH4 conversion to 60% and syngas selectivity to 10%. Moreover, optimizing the inlet CO2 concentration further modulates the redox state of LaFe0.4Co0.6O3. Benefiting from optimized oxidation protocols, the material retained steady performance over 100 redox cycles, sustaining 96–98% CH4 conversion, 92.9–95.4% CO selectivity, 93.9–96.8% H2 selectivity, and 91–93% CO2 utilization efficiency. This study proposes plausible design guidelines for perovskite oxygen carriers tailored to sustainable syngas synthesis via CLRCS and provides fundamental structural and operational references for future reactor scale-up and renewable-energy matching of this carbon capture process.