Simulation of the non-oxidative methane conversion with a catalytically active carbonaceous overlayer

The oxygen-free conversion of methane on transition-metal catalysts could be an interesting alternative to the oxygen-containing conversion (OCM) due to its higher selectivity towards higher hydrocarbons (C2+). So far, the main obstacle has been the low conversion rate compared to the OCM process. This is mostly ascribed to the fact that oxygen-free CH4-conversion is accompanied by a quick deposition of a carbonlayer on the metal surface under atmospheric pressure. This carbonlayer consists of several different species and has been held responsible for catalyst poisoning by the catalyst models discussed in literature. Kinetic simulations with a new catalyst model assuming one of the species forming the carbonlayer, a carbidic-like species C(s), being catalytically active towards CH4-conversion yields qualitatively good accordance with experimental data.