Bio-templated hierarchical ZSM-5 supported NiFe catalysts for selective hydrodeoxygenation of fatty acids to biofuel

This study presents a high-performance catalyst for sustainable biofuel production, synthesizing NiFe bimetallic catalyst on hierarchical ZSM-5 (NiFe-RH-Z5) using rice husk as a green silicon source and structural template. The resulting material features a multi-scale porous architecture that enhances mass transport and active site accessibility. In the hydrodeoxygenation (HDO) of stearic acid, the optimized 7Ni3Fe-RH-Z5 catalyst achieves complete conversion with 92% selectivity to n-octadecane (C 18 alkane), significantly outperforming monometallic analogues. Comprehensive characterization reveals a synergistic mechanism: Fe species adsorb oxygenated intermediates, while Ni sites dissociate hydrogen, collectively steering the pathway toward selective C O bond cleavage and minimizing carbon loss. Furthermore, molecular dynamics simulations confirm a 3.75-fold increase in the diffusion coefficient of stearic acid within the bio-templated hierarchical pores compared to conventional ZSM-5 (Z5). The reaction mechanism, proceeding through an aldehyde intermediate to the C 18 alkane, is unequivocally verified by in-situ spectroscopic and isotopic experiments. This work provides a sustainable strategy for designing efficient catalysts by simultaneously engineering bimetallic synergy and hierarchical diffusion pathways for advanced biofuel production.