From plastic waste pyrolysis to fuel: impact of process parameters and material selection on hydrogen production

Hydrogen is an energy carrier that can be utilized in various applications, including power plants, the synthesis of high-value products, and clean transportation fuels without emissions. Hence, hydrogen is a potential candidate that can replace fossil fuels and reduce environmental pollution. The high demand for plastics is driving the plastics production rate to increase yearly, leading to a great accumulation of plastic waste materials resulting in a severe burden on the environment. Thermo-catalytic conversion of plastic waste materials to hydrogen and other high-value fuels is a promising route that can efficiently provide an ideal long-term solution necessary to overcome this environmental challenge. Developing durable and high-efficiency catalysts that can immerge hydrogen production from plastic wastes on the industrial scale is still a potential challenge for researchers. This study comprehensively summarizes and discusses the recently published literature for hydrogen production from plastic waste materials using different thermo-catalytic processes, including pyrolysis, pyrolysis-air gasification, pyrolysis-steam reforming, pyrolysis- (CO₂) dry reforming, and pyrolysis-plasma catalysis. The scope of this review is to focus on the influence of catalysts and supports, catalysts synthesis method on the production yield of hydrogen, and the impact of several crucial reaction parameters like pyrolysis temperature, catalytic temperature, a catalyst to plastic, and steam to plastic ratios is inclusive in this review as well. The conclusions of this review study will be extremely valuable for researchers interested in the sustainable generation of H₂ from plastic waste materials.