Hydrogen production from plastic waste processing: A review

Plastic waste is both a critical pollution problem and a promising resource for low-carbon hydrogen. This review summarizes thermochemical and emerging routes for H 2 production from plastic waste, focusing on pyrolysis-integrated methods, i.e., pyrolysis catalytic steam reforming (PCSR), pyrolysis catalytic dry reforming (PCDR), pyrolysis catalytic oxidative steam reforming (PCOSR), pyrolysis plasma catalytic reforming (PPCR), and microwave-assisted pyrolysis (MAP), alongside photo-reforming (PR), electro-reforming (ER), and flash Joule heating (FJH). The different alternatives were compared in terms of H 2 yields, gas compositions, and the influence of operating variables such as temperature, catalysts, and feed characteristics. Moreover, the subsequent H 2 purification via pressure swing adsorption (PSA) and membranes is also assessed. Among reported systems, PCSR and PCDR show the highest and most scalable H 2 production, with pilot-scale demonstrations, while PR and ER provide high-purity H 2 under mild conditions but remain limited in throughput. Remaining challenges include catalyst deactivation, energy and carbon efficiency, process integration, and techno-economic feasibility, which must be addressed to enable large-scale deployment of plastic-to-hydrogen technologies within a circular H 2 economy.