Sustainable hydrogen production from aluminium waste: Reactor technologies, environmental benefits, and system‐level integration

Abstract Aluminium‐waste hydrolysis is a potential route for decentralized hydrogen generation because it can use post‐consumer and industrial aluminium residues while reducing dependence on continuous electricity input during the reaction. This review critically evaluates aluminium waste‐based hydrogen production by linking reaction chemistry, oxide‐layer passivation, reactor design, performance benchmarking, techno‐economic assessment (TEA), life cycle assessment (LCA), safety, and system‐level integration. Reported hydrogen yields vary because of differences in alloy composition, oxide thickness, surface pretreatment, sodium hydroxide (NaOH) concentration, temperature, reactor hydrodynamics, and gas‐collection methods. Continuous‐flow and heat‐assisted reactors generally provide better reaction stability than simple batch reactors. Still, their scale‐up remains limited by corrosion, fouling, alkaline recovery, hydrogen purification, feedstock inconsistency, and aluminium hydroxide sludge management. Reported levelized cost of hydrogen (LCOH), energy return on investment (EROI), carbon dioxide (CO 2 ) reduction, and circularity values should therefore be interpreted as condition‐dependent ranges rather than universal indicators. The review also discusses machine learning (ML), digital twins, predictive monitoring, and artificial intelligence (AI)‐assisted fuel‐cell energy management as future tools for improving reactor stability and hybrid renewable integration. Key research needs include standardized reporting, uncertainty‐based TEA and LCA, long‐duration pilot testing, safe scale‐up, closed‐loop NaOH recovery, and validated utilization of byproducts.