Theoretical study of the mechanism of hydrogen production by catalytic methane decomposition on the carbon black catalyst.

Catalytic methane decomposition (CMD) is a promising chemical process for hydrogen production from natural gas with zero CO 2 emissions. In the present work we perform a systematic study of CMD on the graphene edge as a model of the carbon catalyst surface. Atomistic first-principles calculations (DFT level of theory) were performed to obtain the parameters of elementary reactions including the formation of active sites, interaction of methane molecules with these active sites and regeneration of the carbon catalyst surface. Our findings show that methane pyrolysis on the carbon catalyst is a unique heterogeneous radical chain process in which active sites are migrating over the catalyst surface via gas phase radical transport. Based on quantum-chemistry calculations, detailed kinetic mechanism of CMD on the carbon catalyst was developed and verified with respect to the latest experimental data. Calculated effective activation energies and methane conversions in CMD process are in reasonable agreement with experimental data. The present investigation of the mechanism of hydrogen production by CMD process on carbon catalyst can be useful for optimization of this process taking into account degradation of the carbon catalyst. • Systematic study of hydrogen production by catalytic methane decomposition (CMD) was performed. • DFT calculations reveal critical role of unterminated C atoms with dangling bonds. • Developed a detailed CMD kinetic mechanism validated against experimental data. • CMD identified as a self-sustaining heterogeneous radical chain process. [ABSTRACT FROM AUTHOR]