Acidity regulation of Ni–Fe/ZSM-5 catalysts for enhanced lipid deoxygenation toward renewable diesel production

Abstract

Catalytic deoxygenation of lipids provides a promising route for producing renewable diesel-range hydrocarbons. Herein, a series of Ni–Fe/ZSM-5 catalysts with different Si/Al ratios were prepared to clarify the correlation between catalyst acidity and lipid deoxygenation performance. Comprehensive characterization confirmed that adjusting the Si/Al ratio could precisely regulate the acidity, metal dispersion and textural properties of the catalysts, which significantly governed catalytic activity and product selectivity. Notably, the Ni–Fe/ZSM-5 catalyst with a Si/Al ratio of 25 achieved the best activity and maximum selectivity toward diesel-range alkanes. The appropriate acid site density and highly dispersed Ni–Fe bimetallic sites facilitated the hydrodeoxygenation (HDO) pathway and simultaneously inhibited undesired cracking reactions. Additionally, the Ni–Fe synergistic effect effectively improved catalytic stability. This work demonstrates that acidity regulation of ZSM-5-supported non-noble metal catalysts is an effective strategy for enhancing lipid deoxygenation toward renewable diesel production.