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-Nb 3 Al x ) with different Nb/Al ratios, c-Nb, c-Al, c-Nb 3 Al 1 , c-Nb 3 Al 2 and c-Nb 3 Al 3 were synthesized and applied to CFP of lignin. Among these catalysts, c-Nb 3 Al 2 exhibits excellent deoxygenation ability and the highest selectivity for MAHs (77.0 %). The selectivity and deoxygenation capacity of c-Nb 3 Al 2 for MAHs were higher than H-ZSM-5 (25) as a control. It was attributed to the large external surface area (90 m 2 g -1 ), mesoporous structure (16.15 nm) and high acid amount (2.00 mmol NH 3 /g cat ) of c-Nb 3 Al 2 . The c-Nb 3 Al 2 has good stability and can be regenerated by simple calcination . The selectivity of the regenerated c-Nb 3 Al 2 for MAHs was still high at 70.1 %. Guaiacol was used to compare the difference in the deoxygenation capacity of c-Nb 3 Al 2 and H-ZSM-5.