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 (H-2-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 H-2 and highly selective syngas (with H-2/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.