Mo Improves Stability of Ni/HZSM-5 Catalyst in Fatty Acid Hydrodeoxygenation

Enhancing catalyst stability is crucial for reducing production costs and ensuring stable plant operation over the long-term. Ni/HZSM-5 catalysts undergo rapid deactivation during the hydrodeoxygenation of stearic acid. To address this issue, a series of Ni/HZSM-5 catalysts modified with different metal additives were prepared via impregnation. Among these, the Mo-modified catalyst (NiMo/HZSM-5) exhibited significantly enhanced stability. Specifically, it achieved 89.6% conversion and 62.7% alkane selectivity after 15 reaction cycles, whereas the unmodified Ni/HZSM-5 catalyst’s conversion decreased to below 50% after only five cycles. Characterization revealed that Mo addition strengthened the metal–support interaction, effectively suppressing metal agglomeration and metal leaching during the reaction. Additionally, the activities of the two catalysts were compared, and a parametric study was conducted on the NiMo/HZSM-5 catalyst. This work demonstrates that Mo modification is an effective strategy to enhance the long-term stability of Ni/HZSM-5 catalysts in the hydrodeoxygenation of stearic acid.