Advances in Catalyst Design for the Conversion of Methane to Aromatics: A Critical Review

Abstract

The catalytic methane aromatization (CMA) via the non-oxidative approach is increasingly becoming an interesting process for natural gas, shale gas and biogas valorization. However, the design of catalytic materials that could produce very high methane conversion and aromatics selectivity at affordable stability is still difficult. We have carefully documented herein a comprehensive literature survey on the advances in different catalysts designed, characterized and evaluated for the CMA reaction in the recent times. Details on metal-modified zeolite systems including the active sites identification, role of different metals and their loadings, reaction mechanisms and influence of synthetic and catalytic parameters were substantially discussed. The scope was extended to include zeotypes, oxides, un-modified Mo-based compounds and associated catalysts recently evaluated. There are indications that the powdered GaN material is currently been considered as a CMA catalyst. Therefore, relevant studies were carefully surveyed and discussed. In all cases, parameters varied for ensuring conversion and selectivity control were simultaneously highlighted. The paper identified new research paths based on the areas partly explored for further investigations.