Hydrogen represents a pivotal element in transforming the current energy system as its application as a fuel or reducing agent in critical industrial sectors, including transportation and metallurgy, can enhance energy diversity and availability while offering the opportunity to reduce greenhouse gas emissions [1]. However, producing H₂ using conventional methods is associated with the generation of high volumes of carbon dioxide [2]. Therefore, extensive research activities concentrate on developing alternative processes with decreased CO₂ footprints.

Methane pyrolysis in liquid metallic catalysts is an attractive process that shows excellent potential, as its specific energy demand is comparable to that of steam methane reforming, but no CO₂ is emitted due to the base reaction [3], [4]. Furthermore, generated pyrolysis carbon is a valuable product with many possible applications [5].

This work investigates the influence of different compositions of the utilized metal bath on produced pyrolysis carbon. The focus is on modulating its physical properties, especially with regard to marketability and impact on the overall process economics while sustaining sufficient hydrogen yield.