Enhancement of methanation of bio-syngas over CeO₂-modified Ni/Al₂O₃ catalysts

CeO₂ modified Ni/Al₂O₃ catalysts were developed for synthetic natural gas (SNG) from bio-syngas methanation. Physiochemical properties of the CeO₂ modified Ni/Al₂O₃ catalysts were characterized by N₂ physical adsorption (BET), scanning electron microscopy (SEM), temperature-programmed reduction of hydrogen (H₂-TPR), X-ray diffraction (XRD) and thermo gravimetric analyzer (TGA). The bio-syngas methanation tests showed that adding 60 wt.% of CeO₂ in the Ni/CeO₂-Al₂O₃ catalyst presented excellent bio-syngas methanation performances (91.6% carbon oxides conversion with 92% CH₄ selectivity) at low temperature (350 °C). The characterization results indicated that adding of CeO₂ into Ni/Al₂O₃ strengthened the NiO-CeO₂ interaction via the weakening of the interaction between Ni species and Al₂O₃, facilitating the separation of NiO from NiAl₂O₄. The optimal CeO₂ content of 60 wt.% was obtained to disperse well Ni species and increase active metallic Ni sites, promoting the catalytic performances for bio-syngas methanation to SNG.