Activity and Structure of Mo-HZSM5 Catalysts for Non-Oxidative Methane Dehydroaromatization

Non-oxidative dehydroaromatization (DHA) of methane over Mo/HZSM-5 catalysts offers an attractive route for the production of valuable aromatic compounds such as benzene , toluene , and xylene (BTX).  However , there are numerous technical challenges that need to be overcome for developing highly efficient systems.  Under typical operating conditions , catalyst deactivation is mainly attributed to coking of the zeolite.  Furthermore , there is a long-standing debate in the scientific literature regarding the transformation of MoO3 to active MoxCy species in these catalysts and deactivation mechanisms.  Thus , a better understanding of structure-activity relationships will lead to rational design of DHA catalysts , which in turn will facilitate advances in methane utilization technologies. We have synthesized and investigated Mo-based catalysts supported on HZSM-5 containing different promoters and varying degrees of acidity.  Results from ex situ and in situ surface and bulk characterization techniques have shed light on the factors that control the activity , selectivity , and stability of these catalysts.  Correlations between the catalytic performance and MoxCy species associated with the Brönsted acid sites of HZSM-5 will be discussed.