Catalytic pyrolysis of lignin to aromatic hydrocarbons over Nb/Al oxide catalyst

Catalytic fast pyrolysis (CFP) of lignin aiming monocyclic aromatic hydrocarbons (MAHs) is attractive. Five metal oxide catalysts (named c-Nb3Alx) with different Nb/Al ratios, c-Nb, c-Al, c-Nb3Al1, c-Nb3Al2 and c-Nb3Al3 were synthesized and applied to CFP of lignin. Among these catalysts, c-Nb3Al2 exhibits excellent deoxygenation ability and the highest selectivity for MAHs (77.0%). The selectivity and deoxygenation capacity of c-Nb3Al2 for MAHs were higher than H-ZSM-5 (25) as a control. It was attributed to the large external surface area (90 m2g-1), mesoporous structure (16.15 nm) and high acid amount (2.00 mmolNH3/gcat) of c-Nb3Al2. The c-Nb3Al2 has good stability and can be regenerated by simple calcination. The selectivity of the regenerated c-Nb3Al2 for MAHs was still high at 70.1%. Guaiacol was used to compare the difference in the deoxygenation capacity of c-Nb3Al2 and H-ZSM-5.