Nonoxidative activation of methane

Effective utilization of methane remains one of the long-standing problems in catalysis. Over the past several years, various routes, both direct and indirect, have been considered for the conversion of methane to value-added products such as higher hydrocarbons and oxygenates. This review will focus on the range of issues dealing with thermal and catalytic decomposition of methane that have been addressed in the last few years. Surface science studies (molecular beam methods and elevated-pressure reaction studies) involving methane activation on model catalyst systems are extensively reviewed. These studies have contributed significantly to our understanding of the fundamental dynamics of methane decomposition. Various aspects of the nonoxidative methane to hi-her hydrocarbon conversion processes such as high-temperature coupling and two-step low-temperature methane homologation have been discussed. Decomposition of methane results in the production of COx-free hydrogen (which is of great interest to state-of-the-art low-temperature fuel cells) and various types of carbon (filamentous carbon, carbon black, diamond films, etc.) depending on the reaction conditions employed; these issues will be briefly addressed in this review.