Redox cycling of CuFe₂O₄ supported on ZrO₂ and CeO₂ for two-step methane reforming/water splitting

CuFe₂O₄ supported on ZrO₂ and CeO₂ for two-step methane reforming was evaluated to determine if it could enhance the reactivity, CO selectivity and thermal stability of CuFe₂O₄. Two-step methane reforming consists of a syngas production step and a water splitting step. CuFe₂O₄ supported on ZrO₂ and CeO₂ was prepared using an aerial oxidation method. Non-isothermal methane reduction was carried out on TGA to compare the reactivity of CuFe₂O₄/ZrO₂ and CuFe₂O₄/CeO₂. In addition, a syngas production step was performed at 900 °C and water splitting was conducted at 800 °C alternatively five times to compare the methane conversion, CO selectivity, cycle ability and hydrogen production by water splitting in a fixed bed reactor. If the 1st syngas production step results are excluded due to over-oxidation, CuFe₂O₄/ZrO₂ and CuFe₂O₄/CeO₂ showed approximately 74.0-82.8% and 60.3-87.5% methane conversion, respectively, and 44.0-47.8% and 65.2-81.5% CO selectivity, respectively. Using CeO₂ and ZrO₂ as supports effectively improved the reactivity and methane conversion compared to CuFe₂O₄. CuFe₂O₄/ZrO₂ showed high methane conversion due to the high phase stability and thermal stability of ZrO₂ but the selectivity was not improved. After 5 successive cycles, the CeFeO₃ phase was found on CuFe₂O₄/CeO₂. Furthermore, methane conversion, CO selectivity and the amounts of hydrogen production of CuFe₂O4/CeO₂ increased with increasing number of cycles. Additional test up to the 11th cycle on CuFe₂O₄/CeO₂ revealed that CeO₂ is a better support that ZnO₂ in terms of the reactivity and CO selectivity.