Methane cracking in molten tin for clean hydrogen and carbon production: an experimental study

Methane cracking is considered a bridge technology between gray and green hydrogen production processes. In this work, an experimental study of methane cracking in molten tin is presented. The influence of the reactor’s geometric parameters and the methane injection system is investigated due to their effects on bubble formation, and consequently, gas residence time. The influence of temperature is also studied in the range of 950–1070 °C. Carbon morphology was analyzed using scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) surface area analysis. The results showed that the reactor diameter affects methane conversion, with larger reactors leading to higher conversions. The diameter of the injection capillary also influences conversion: smaller capillary diameters produce smaller bubbles and slightly increase residence time within a narrow range. The resulting carbon exhibits sheet-like structures and results more ordered when produced at higher temperatures.