Production of Carbon\nFibers Using a Molten Cu–In\nCatalyst for Methane Pyrolysis

Molten metal catalysts for methane pyrolysis and dry\nreforming\nare becoming recognized for their potential in decarbonization efforts.\nTheir use in bubble column reactors facilitates continuous operation\nby allowing the produced carbon to float to the surface for removal.\nWhile most reported molten metals produce low-value amorphous carbon\nor graphitic sheets containing some metals, our study introduces a\nCu–In alloy that selectively produces high-purity carbon nanofibers.\nThese nanofibers are tubular and have a smooth or bamboo-like segmented\nstructure with a diameter of approximately 100 nm. We have identified\na droplet-based pathway for the growth of these fibers and removal\nof the droplets, observed consistently across a bubble column reactor,\na surface reactor, and both in the absence and presence of carbon\ndioxide for pyrolysis and dry reforming. The molten Cu–In system\nis shown to outperform other molten metal catalysts, producing fibers\nwith a purity greater than 99.9% after heat treatment.