The increasing demand for sustainable aviation fuel (SAF) requires efficient catalytic systems capable of converting renewable waste feedstocks into jet-fuel-range hydrocarbons. However, conventional catalytic cracking catalysts often exhibit limited selectivity toward the C12–C16 fraction, insufficient deoxygenation activity, and rapid catalyst deactivation. In this study, a novel bifunctional nickel-dispersed sulfated zirconia integrated with natural zeolite (Ni-SZ/Na-zeolite) catalyst was developed for the selective conversion of waste cooking oil (WCO) into SAF through pyrolytic catalytic cracking. Unlike previously reported hydrocracking or conventional zeolite-supported catalyst systems, the developed catalyst synergistically combines metallic Ni active sites for deoxygenation, strong Brønsted–Lewis acidic sulfated zirconia for enhanced cracking activity, and mesoporous natural zeolite structures for improved reactant diffusion and hydrocarbon selectivity. Structural and physicochemical properties were characterized using FTIR, XRD, BET, and SEM–EDS analyses, confirming the successful formation of mesoporous bifunctional catalyst structures with highly dispersed Ni species. Process optimization using Response Surface Methodology–Central Composite Design (RSM-CCD) evaluated the effects of reaction temperature and Ni loading on oil liquid product (OLP) yield and bio-avtur selectivity. Among the investigated catalysts, Ni-3/SZ exhibited the most favorable textural properties, with a pore diameter of 6.72 nm and a pore volume of 0.0589 cm 3 g -1 . Under optimal conditions of 443°C and 3 wt% Ni loading, the process achieved an OLP yield of 76.24% and bio-avtur selectivity of 71.13%. GC–MS analysis confirmed the dominance of paraffinic hydrocarbons within the C12–C16 range. These findings demonstrate that the synergistic integration of Ni active sites, sulfated zirconia acidity, and natural zeolite mesoporosity provides an effective catalytic strategy for enhancing sustainable aviation fuel production from renewable waste feedstocks.
Pawoko et al. (Fri,) studied this question.