Hydrogen is increasingly recognized as a critical vector in decarbonizing industrial energy systems. Its utilization as a fuel and reducing agent in sectors such as metallurgy and chemical processing has the potential to reduce greenhouse gas emissions and enhance energy system resilience significantly [1]. However, conventional hydrogen production, e.g., via steam methane reforming, is associated with substantial CO₂ emissions, necessitating the development of more ecological alternatives [1]–[4].

Methane pyrolysis in metallic melts has emerged as a promising route for CO₂-free hydrogen generation [3], [5]. In this process, methane is decomposed in an oxygen-free atmosphere in the presence of a liquid-metal catalyst to form solid carbon and gaseous hydrogen [3], [5]. The process operates at a comparable specific energy demand to steam methane reforming but circumvents direct carbon dioxide formation [3], [4]. The pyrolytic carbon produced constitutes a potentially valuable co-product whose physicochemical properties strongly influence its marketability and the overall economic viability of the process [4].

This study focuses on the specific energy demand of methane pyrolysis in molten metals, combining theoretical analysis with experimental findings. The influence of the nitrogen and methane inputs on energy consumption is investigated in laboratory scale-ups. The results enable a comparison with conventional hydrogen production routes and provide critical insights for designing integrated methane pyrolysis systems aimed at sustainable hydrogen and carbon co-production.