Catalytic Methane Dehydroaromatization with Stable Nano Fe Doped on Mo/HZSM-5 Synthesized with a Simple and Environmentally Friendly Method and Clarification of a Perplexing Catalysis Mechanism Dilemma in This Field for a Period of Time

Dehydroaromatization of methane to aromatics provides a promising approach for cost-effective conversion of methane. This work was designed to study the promoting effect of nano Fe on the Mo/HZSM-5 catalyst in methane dehydroaromatization (MDA). Mo/HZSM-5 and nano-Fe modified catalysts were synthesized and then evaluated in a fixed-bed reactor along with an integrated online gas chromatography and a mass spectrometry system. The fresh or/and spent catalysts were characterized by ICP-MS, H2-TPR, CH4-TPSR, NH3-TPD, XRD, SEM, TEM, N2 adsorption/desorption, TGA, and DRIFT spectroscopy. Nano-Fe doped Mo/HZSM-5 catalysts prepared with an innovative method show enhanced MDA performances especially stability. Moreover, research demonstrates that carbon nanotubes can not only form on the Mo/HZSM-5 catalyst without the addition of Fe but also exist for a long time, which clarifies the carbon nanotubes formation mechanism. It was concluded that nano Fe plays an important role in promoting the growth of carbon nanotubes and thus the activity and stability of the catalysts.