Catalytic Pyrolysis of Biomass Tar Using Different Ni-Based HZMS-5: Influence of Promoters Characteristics on Hydrogen-Rich Gas Formation

The study specifically focused on the effect of different promoter characteristics and interactions between Ni-Ce, Ni-Fe, and Ni-Mg on the physicochemical properties of Ni/HZSM-5 catalyst. The results revealed that promoter characteristics are important when determining the form of nickel atomic species, structural properties and catalytic abilities of catalysts. The Fe-modified Ni/ZSM-5 catalyst has the most effective catalyst for hydrogen-rich gas production with the highest gaseous efficiency of 63.4 wt.%, gas yield of 118.6 mL/g toluene, H2 yield of 53.4 mL/g toluene at 800 °C pyrolysis for 1 hour. However, the stability of catalysts improved by incorporating CeO2, the H2 yield was lower (40.3 mL/g). Ni-Mg/HZSM-5 catalyst was slightly less stable. The smaller crystal particles (3.1 nm), high surface area (219.5 m2/g), and sufficient loading (4 wt.%) for Ni-Fe catalysts provide efficient active sites and promote the process for pyrolysis biomass tar. Catalyst’s deactivation is associated with char deposition.