Hydrogen production by catalytic methane decomposition: Carbon materials as catalysts or catalyst supports

Hydrogen and carbon materials are two promising research topics in the field of environmentally benign energy and material science, respectively. Hydrogen production by methane decomposition can avoid the formation of COx during the fossil fuel life cycle, paving the route for the development of a low-carbon hydrogen economy. The development of state-of-the-art catalysts plays a crucial role in efficient methane conversion for co-production hydrogen and nanocarbons by catalytic methane decomposition (CMD), and considerable effort has been made to develop various carbon-based catalysts in this field. This work provided a critical review on the theoretical and technological background of CMD over carbon-based catalysts, and summarized the recent research progress on the diverse commercial (i.e., activated carbon, carbon black, graphite, carbon nanotubes, carbon nanofibers, etc.) or non-commercial carbon materials (including mesoporous carbon, hierarchical porous carbons, heteroatom doped carbon, carbon supported catalysts, and so on.) as catalysts or catalyst supports and their applications in CMD. The process descriptions along with operating parameters of CMD (such as reaction temperature, pressure, space velocity, feedstock purity, reactor type and material) and the catalyst characteristics (such as preparation method and conditions, catalyst type and particle size, textural properties and surface chemistry) were discussed. Additionally, potential origin of the catalytic activity, microscopic understanding on the catalyst deactivation and regeneration, perspectives and challenges were also outlined.