From waste plastic to hydrogen fuel: selective conversion through advanced catalytic technologies

The massive amount of discarded plastic waste has caused global environmental pollution and resource scarcity. Converting plastic wastes into valuable chemicals and fuels have emerged as promising strategies to promote a circular economy. Especially, selective conversion of plastic waste to hydrogen through advanced catalytic technology is more responsive to the development needs of the green economy era. In this review, we summarized current advances on plastic-to-hydrogen by thermocatalysis/photo-thermal catalysis, photocatalysis, electrocatalysis, and photo-electrocatalysis. The design of efficient catalysts, understanding of structure-activity relationship and catalytic mechanism, optimization of reaction systems, and practical applicability in each method are highlighted and discussed in detail. We also assessed the economic feasibility and environmental impact of plastic-to-hydrogen technologies based on techno-economic analysis and life cycle assessment. The ongoing challenges and future research directions in this area are critically discussed. Our goal is to elucidate the catalytic mechanisms and principles of catalyst design, providing guidance for the development of efficient catalysts to enhance catalytic activity, hydrogen selectivity and purity, and plastic processing capabilities. We believe that this review will inspire more creativity in designing such win–win catalytic reaction systems.