Enhancing aviation sustainability: bimetallic Ni–Co catalysts for bio-jet fuel from palm kernel oil

The production of bio-jet fuel from renewable sources such as palm kernel oil (PKO) biomass has been extensively been studied for the production of transportation fuel due to its availability. Hence, this study was focused on the production of bio-jet fuel (BJF; C₈-C₁₆) derived from PKO via catalytic deoxygenation (DO) reaction under H₂-free environment over Ni_x-Co_x supported on magnetite (Fe₃O₄) catalyst. The Ni and Co concentrations have been kept within 0.5–0.75 wt% to optimize the synergistic interaction between the metals and the support. The result indicated that Ni_0.5-Co_0.5/Fe₃O₄ catalyst exhibited high surface area (156.75 m²g⁻¹) with weak (437.1 μmol/g) + strong (14601.0 μmol/g) acidic sites. In a preliminary PKO catalytic DO study conducted at 350℃ for 3 h using a 5 wt% catalyst loading under an inert N₂ atmosphere, the results revealed that the Ni_0.5-Co_0.5/Fe₃O₄ catalyst exhibited higher DO activity, achieving approximately 91 % hydrocarbon selectivity. The majority of the product was in the BJF (C₈-C₁₆) fraction, accounting for 95 %. The data also showed that the Ni_0.5-Co_0.5/Fe₃O₄ catalyst was more selective towards BJF, with a selectivity value of 77 %, the highest observed for the C₁₁ carbon chain. Based on the kinetic and deactivation study of the Ni_0.5-Co_0.5/Fe₃O₄ catalyst over a 500mins DO reaction, the results revealed that the primary cause of catalyst deactivation was coking activity. It also appeared that a higher DO temperature (350℃) positively affected coking activity. Interestingly, a longer reaction time at a lower DO temperature mitigated coking activity, with coke deposition reaching approximately 5 wt%. The Ni_0.5-Co_0.5/Fe₃O₄ catalyst demonstrates significant commercial viability for industrial bio-jet fuel production owing to its exceptional deoxygenation efficacy and adequate coking resistance.