Study on fast pyrolysis of agricultural waste corn stover to aromatic hydrocarbons over V2O5-modified hierarchical ZSM-5 catalyst

V 2 O 5 -modified hierarchical ZSM-5 catalysts were synthesized. • The catalysts enhanced deoxygenation during biomass pyrolysis. • The obtained bio-oil was enriched in aromatic hydrocarbons. • The bio-oil upgrading mechanism over the catalysts was elucidated. Biomass catalytic pyrolysis is a key technology for converting biomass into high-value bio-oil as a sustainable alternative to fossil resources. To address the limitations of conventional microporous zeolites, such as mass transfer constraints and insufficient deoxygenation capability during bio-oil upgrading, this study employed V 2 O 5 -modified hierarchical ZSM-5 zeolite as the catalyst and corn stover as the feedstock to investigate the catalytic upgrading process. A hierarchical ZSM-5 zeolite with intercrystalline mesopores was first prepared via a mechanical ball milling-recrystallization method, followed by V 2 O 5 loading using wet impregnation. The catalyst's structure and properties were systematically characterized. Fast catalytic pyrolysis experiments of corn stover showed that the Me 0.004 support possesses a well-defined hierarchical pore structure, which facilitates the diffusion and reaction of large molecules in bio-oil. The redox properties of V 2 O 5 promoted the catalytic deoxygenation of biomass macromolecules, yielding smaller molecular intermediates. These intermediates subsequently underwent a series of reactions, including Diels–Alder cyclization and dehydrogenative aromatization, leading to the formation of aromatic hydrocarbons (AHs) over the ZSM-5 catalyst. In particular, the V2/Me 0.004 catalyst achieved an aromatic hydrocarbon yield 1.94 times higher than that of conventional ZSM-5. Based on pyrolysis experiments with model compounds, possible reaction pathways for AHs formation from corn stover over the developed catalyst were proposed. This study provides a theoretical foundation and technical support for the production of high-value chemicals, contributing to the advancement of efficient biomass resource utilization. Download: Download high-res image (540KB) Download: Download full-size image