Methane steam reforming for eco-friendly H₂ production using atmospheric-pressure microwave steam plasma

Hydrogen (H₂) is gaining attention as a clean fuel and a key future energy resource for the future, with expanding applications in power generation, clean transportation, and chemical synthesis. To meet the growing demand for hydrogen, recently, various production methods have been developed. In this work, steam plasma reforming and its combination with catalytic reforming were developed and considered to address limitations of conventional techniques, such as high energy consumption and significant CO₂ emissions. Under various conditions, steam plasma reforming demonstrated rapid reaction kinetics and low CO₂ emissions, whereas catalytic reforming resulted in higher CO₂ emissions. In addition, the combination of steam plasma and catalytic reforming enhanced CH₄ conversion and H₂ yield but resulted in increased CO₂ emissions. Notably, the performance of CH₄ reforming in steam plasma was primarily influenced by steam-to-carbon (S/C) ratio. Optimal performance, balancing CH₄ conversion, H₂ yield, and minimal CO₂ production, was achieved at an S/C ratio of 4.7 with 6 kW of power. These results highlight steam plasma reforming as a promising approach for clean H₂ production, particularly for applications requiring reduced CO₂ emissions, such as turquoise hydrogen and syngas generation.