Catalytic pathways towards sustainable aviation fuel production from waste biomass: A systematic review

Sustainable aviation fuel (SAF), derived from renewable resources, presents a practical alternative to Jet-A fuel by mitigating the ecological impact of aviation’s reliance on fossil fuel. Among the available feedstocks, waste biomass and waste oils present key advantages due to their abundance, sustainability potential, and waste valorization benefits. Despite continuous progress in SAF technologies, comprehensive assessments of catalytic routes and their efficiency in transforming waste-based feedstocks into aviation-grade fuels remain limited. This review addresses this gap by systematically evaluating recent studies (2019–2024) that investigate catalytic conversion and upgrading of waste-derived biomass toward SAF production. Selection of thermochemical processes including pyrolysis, gasification, and hydrothermal liquefaction, or biological pathways, is driven by the physicochemical characteristics of the waste. These processes yield intermediates such as biocrude and bio-oils, undergo catalytic upgrading to meet aviation fuel standards. Zeolitic acids, sulfided NiMo or CoMo catalysts, noble-metal/oxide systems, and bifunctional or carbon-based catalysts drive hydroprocessing, deoxygenation, cracking, and isomerisation reactions, delivering high selectivity toward C8-C16fractions. Performance, mechanisms, and selectivity of these catalysts are critically assessed in relation to feedstock characteristics and operating conditions. Key factors such as metal-acid balance, hierarchical porosity, and tolerance to heteroatoms enhance catalytic efficiency. Persistent challenges including deactivation, coking, sintering, and feedstock impurities continue to limit long-term performance and scalability in waste-to-SAF applications. Mitigation strategies, including oxidative and resulfidation regeneration and support modification, have demonstrated improved stability. Moreover, waste-derived catalysts and circularity enhance process sustainability. Future work should align catalyst design with feedstock pretreatment and techno-economic assessments to scale sustainable and cost-effective waste-to-SAF pathways.