Theoretical investigation of the methane cracking reaction pathways on Ni (111) surface

• Published in: Chemical physics letters Vol. 639; pp. 205 - 210
• Main Authors: Li, Jingde, Croiset, Eric, Ricardez-Sandoval, Luis
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 16.10.2015
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2015.09.030

•Reaction networks in methane cracking were investigated using DFT calculations.•Bimolecular reactions provide alternate kinetic favorable routes for methane cracking.•CH4 directly reacting with CH specie should be added in methane cracking mechanism.•The study explains the absence of gas phase C2 hydrocarbon in methane cracking. A comprehensive methane cracking reaction pathway was investigated by performing density functional theory (DFT) calculations. In addition to the sequential dissociation reaction, i.e. CH4→CHx+(4−x)H→C+2H2, a more sophisticated surface reaction network was studied, i.e. CHx+C→CHx−1+CH. The results show that CHx dehydrogenation is promoted with a low energy barrier through bimolecular reaction and provide an alternative kinetic favorable route for methane cracking. This study also demonstrates that the production of gas phase C2 hydrocarbon species, e.g. C2H2 and C2H4, in methane cracking reaction is unlikely due to the high barrier energy of C2H3 formation and their strong adsorption energy on Ni (111).