Toward Efficient Bio-jet Fuel Production via Atmospheric Hydrotreating: Insight into the Effect of Co/HZSM-5, Mo/HZSM-5, and CoMo/HZSM-5 Catalyst Arrangements

Growing environmental concerns associated with fossil-based jet fuel have spurred intensive research into renewable alternatives for the green aviation industry. In this study, HZSM-5 catalysts impregnated with cobalt (Co) and/or molybdenum (Mo) were successfully synthesized via a simple and eco-friendly spray impregnation method, forming mono- and bimetallic catalysts. For the first time, these catalysts were evaluated in a double-bed reactor system using customized monolayer and bilayer configurations for the atmospheric hydrotreating of crude palm oil into bio-jet fuel. The incorporation of Co and/or Mo modified the physicochemical properties of HZSM-5, reducing its specific surface area and total pore volume while increasing the average pore diameter and total acidity. Among the configurations, the Mo/Z (top)–Co/Z (bottom) bilayer catalyst demonstrated superior performance, achieving a 45.75% liquid product conversion and a 44.97% bio-jet fuel yield with 99.14% selectivity at 350–450 °C. This arrangement effectively promoted hydrodeoxygenation and hydrocracking reactions, producing bio-jet fuel with a freezing point of − 52 °C after vacuum distillation, in compliance with ASTM aviation fuel standards. The catalyst maintained stable performance over five consecutive runs with minimal yield decline, underscoring its durability. Overall, this study presents a promising, cost-effective approach for sustainable aviation fuel production with
strong potential for industrial-scale application.