Promoted Mo/H-ZSM-5 Catalysts for Methane Dehydroaromatization: from Powder to Extruded Material

To bridge the gap between research and technical catalysts for methane dehydroaromatization (MDA), a procedure for producing extruded promoted Mo/ZSM-5 catalysts was developed. The influence of the type (M = Fe, Co, Ni) and content (0.1–1 wt.%) of the promoter on the textural, structural, electronic and redox characteristics and catalytic properties of 2Mo/ZSM-5 sample in MDA was studied and optimal composition of promoted M–2Mo/ZSM-5 catalyst was selected. The optimized 0.5Co–2Mo/ZSM-5 catalyst was formed into cylindrical extrudates with a diameter of 4.8 mm and a length of 5.5 mm. The mechanical crushing strength, physicochemical and catalytic properties of the extrudates were regulated by changing the chemical composition (Ca-montmorillonite, SiO2 sol) and content (10–30 wt.%) of the binder, as well as the order of introduction of the metal active component (before or after extrusion). The characteristics of the as-synthesized and spent extruded 0.5Co–2Mo/ZSM-5 catalysts were studied using low-temperature nitrogen adsorption, powder X-ray diffraction, electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, IR spectroscopy of adsorbed CO, temperature-programmed reduction and thermal analysis. The optimal formula for the extruded material and the method for producing it were found. The composite containing 80 wt.% 0.5Co–2Mo/ZSM-5 catalyst and 20 wt.% Ca-montmorillonite binder is characterized by high mechanical crushing strength and suitable catalytic properties in the MDA reaction.