Steam Reforming of Biogas over CeO₂-Coated Ni-Al Plate Catalysts

Hydrogen production via steam reforming of a simulated biogas was achieved in a temperature range of 500-800 °C over a plate-type Ni-Al catalyst. To enhance the catalytic activity of the Ni-Al catalyst, a pretreatment process involving pre-oxidation with sequential reduction was employed prior to the reforming reactions. The activated Ni-Al catalyst exhibited increased methane conversion depending on the pre-oxidation temperature. Studies using X-ray diffraction and scanning electron microscopy suggested that the catalyst surface was restructured upon pretreatment, ultimately improving the catalytic activity. To increase its catalytic stability, CeO₂ was employed additionally as a structural promoter to prevent both Ni sintering and carbon deposition. The durability of the CeO₂-coated Ni-Al catalyst was improved significantly, particularly upon addition of ≥2.8 wt% of CeO₂, with ca. 75 % of CH₄ conversions being achieved without deactivation over 100 h at 700 °C. The influence of the pre-oxidation temperature, reforming temperature, and steam/CH₄ ratio on reforming over a CeO₂-Ni-Al catalyst was also elucidated. In addition, the potential roles of CeO₂ in the enhancement of activity and stability were discussed. (Graph Presented).