Carbonaceous deposition on MoMCM-22 catalysts for non-oxidative dehydro-aromatization of methane: effect of surface aluminum removal and Mo content

摘要

The amount,nature and location of the different types of coke formed during the dehydro-aromatization of methane was studied over molybdenum carbide supported on HMCM-22 zeolite in both the as-synthesized form and after surface aluminum removal (higher stability),at 973 K.TG results confirmed the presence of two types of coke: carbidic and non-carbidic coke.TPO profiles let it clear that the non-carbidic coke deposited on Mo species were higher for the samples for which the ratio Mo species/free Bronsted acid sites is high.The increase in Mo content also caused a significant decrease of the amount of non-carbidic aromatic coke deposited on Bronsted acid sites.