The current work investigated the preparation of Nano-particles of Co/Zn Al2O4 as a catalyst via co-precipitation method. Several analyses, including BET, XRD, HRTEM, EDX, SEM, and FTIR, were used to characterize it. The analysis revealed that the prepared catalyst had an average surface area of 69.20 m2/g, a cross-sectional area of 16.2 m2/molecule, an average particle size of approximately 28 nm, and a pore size of 0.22 cm3/g. The prepared catalyst was used in a bio fuel synthesis process via thermo-catalytic cracking of waste cooking oil (WCO) in a single step batch reactor. Catalyst loading was tested with different weight percentage of 1.5%, 2%, and 2.5%. The pilot study revealed that the best conditions for optimizing bio jet fuel yield were 400 °C, a catalyst loading of 2%, and a reaction time of 30 min.The optimal cut-off from the distillation process of crude liquid bio fuel product which represents a fraction of bio-jet fuel was in the range from 150 to 240 °C.