Improving Metal Dispersion Over Mo-based TNU-9 for Methane Dehydro-Aromatization

Abstract

The initial dispersion and state of the Mo-oxide in the zeolite are crucial factors in the development of the active phase and selectivity toward the target product (benzene, toluene, and naphthalene), which greatly affects the catalytic activity of Mo-doped HTNU-9 in methane dehydro-aromatization (MDA). To investigate their impact on the catalytic activity toward MDA, Mo oxide precursors (α-MoO₃ and commercial MoO₃) are applied in this case. The dispersibility is enhanced by employing solid-phase grinding method of α-MoO₃ precursors onto the HTNU-9 support. SEM, EDS mapping, NH₃-TPD, ¹H MAS NMR, H₂-TPR, Raman, and UV–vis instruments are used to thoroughly investigate the key properties of the Mo-containing HTNU-9 catalysts. Based on the results of the MDA catalytic test, The catalyst generated using the α-MoO₃-modified zeolite carrier has a methane conversion rate that is 13.7% higher than that of the Mo(C)/TNU-9 catalyst (11.4%). The enhanced catalytic activity of the Mo(N)/TNU-9 catalyst is thought to be due to the use of initially scattered Mo-oxide species. During the calcination, α-MoO₃ species is incorporated into the framework and subsequently transforms into more reactive Mo species. The utilization of the Mo(N)/TNU-9 catalyst results in an elevated formation resistance of hard coke and easily-burned polyaromatics.