Development of the supported nickel-baseed catalysts and application in pyrolyzing biomass

The supported nano-NiO/γ-Al₂O₃ catalyst was prepared by deposition-precipitation (DP) method. Different analytical approaches such as XRD, BET, TEM and SEM/EDX were used to characterize the synthesized catalysts. The results showed that the prepared nano-NiO/γ-Al₂O₃ catalysts had a coated structure with a loading of NiO in catalysts over 12 wt %, and they had also a high BET surface area of 124.6 m²/g. The active components of catalyst were spherical NiO nanoparticles coated on the surface of supports with a size range of 12~18 nm. Meantime, the activity of the catalysts to remove tar in the process of biomass pyrolysis was also investigated using a bench-scale combined fixed bed reactor. The experiments demonstrated that the tar yield after adding catalysts was reduced significantly, and the removal efficiency of tar reached to 99% for catalytic pyrolysis at 800°C, while the gas yield after adding catalysis increased markedly. Meanwhile, the compositions of gas products before and after adding catalysts in the process also changed significantly, especially the percentages of H₂ and CO in the product gas after adding catalysts were obviously increased. Therefore, the prepared catalysts showed their excellent catalytic activity for tar removal and syn-gas producation in biomass pyrolysis.