Methane dehydroaromatization using Mo supported on sulfated zirconia catalyst: Effect of promoters

Methane dehydroaromatization (MDHA) is a direct approach of converting methane to aromatics and H2. Mo doped HZSM-5/HMCM-22 are considered as the most active and stable catalysts for MDHA. It is generally thought to involve a process in which Mo oxides convert to MoCy/MoOxCy active species that activate CH4 to C2Hy dimers. In a final step, C2Hy dimers undergo oligomerization on zeolite Br?nsted acid sites. An alternative solid acid support is sulfated zirconia (SZ), which is known to contain strong Br?nsted acidity. Carbon deposition is significant. Here, MDHA is compared to Pt, Pd, Cr, W promoters for Mo/SZ catalyst to decrease carbon deposition and increase aromatics selectivity. The catalysts are characterized using BET, SEM-EDS, DRIFTS, Raman Spectroscopy, XRD, XANES and TPO. Activity varied with different promoters. Less carbon deposition and slower deactivation were observed for Pd, Pt and Cr promoted catalysts, while W promotion resulted in more carbon deposition and rapid deactivation Compared to Pd and W promotion, Pt and Cr increased higher aromatics selectivity for Mo/SZ.