Research progress on thermochemical conversion technologies for hydrogen production from waste plastics

Thermochemical conversion of waste plastics presents a pivotal strategy for simultaneously addressing global plastic pollution and clean hydrogen demand. This review provides a systematic synthesis of established pathways, including catalytic pyrolysis and gasification, alongside emerging electrification technologies such as microwave-assisted conversion and Flash Joule Heating (FJH). Beyond descriptive summaries, we strictly benchmark these routes regarding hydrogen yield, energy efficiency, and techno-economic viability. The analysis reveals distinct trade-offs: while gasification currently offers the lowest levelized cost due to economies of scale, emerging electrified pathways demonstrate superior specific energy efficiency and potential negative production costs via high-value co-products. Critical technical bottlenecks are critically examined, with a focus on deciphering catalyst deactivation mechanisms—specifically coking and heteroatom poisoning—and evaluating scale-up constraints based on industrial pilot cases. Furthermore, by integrating insights from Techno-Economic Analysis (TEA) and Life Cycle Assessment (LCA), we clarify the divergence between economic drivers and environmental benefits. The review concludes by proposing a forward-looking strategic framework that prioritizes impurity-tolerant reactor designs and continuous process integration, aiming to bridge the gap between laboratory technical potential and sustainable industrial realization.