Hydrogen and syngas production from two-step steam reforming of methane over CeO2-Fe2O3 oxygen carrier

Two-step steam reforming of methane (SRM) is a novel chemical looping process towards the production of pure hydrogen and syngas (synthesis gas), consisting of a syngas production step and a water-splitting step. Renewable energy can be used to drive this process for hydrogen production, especially solar energy. CeO₂-Fe₂O₃ complex oxide oxygen carrier was prepared by the impregnation method and characterized by means of X-ray diffractometer (XRD), Raman spectroscopy (Raman) and hydrogen programmed reduction (H₂-TPR). CH₄ temperature programmed and isothermal reactions were adopted to test syngas production reactivity, and water splitting reaction was employed to investigate water-splitting activity. Moreover, two-step SRM performance was evaluated by a successive redox cycle. The results showed that CO-uncontaminated H₂ and highly selective syngas (with H₂/CO ratio close to 2) could be respectively obtained from two steps, and CeFeO₃ formation was found in the first redox cycle and proved to be enhanced by the redox treatment. After 10 successive cycles, obvious CeFeO₃ phase was detected, which may be responsible for favorable successive redox cycle performances.