In situ synthesis of MoS2 nanoflakes within a 3D mesoporous carbon framework for hydrodesulfurization of DBT

Two new mesoporous carbon-supported Co-Mo hydrodesulfurization catalysts with different Co contents have been successfully prepared by one-step vacuum freeze-drying, followed by calcination under a nitrogen atmosphere and washing. Evans-Showell polyoxometalate (NH4)6[Co2Mo10O38H4]center dot 7H2O was used as the Co-Mo precursor instead of the conventional precursors, and the obtained catalysts were structurally characterized by various technologies, including X-ray diffraction, thermogravimetric analy-sis, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelec-tron spectroscopy, H2 temperature programmed reduction, CO temperature programmed desorption and low temperature N2 adsorption-desorption isotherm. The results show that MoS2 particles (4.6 nm and 4.5 slabs) are homogeneously dispersed in the mesoporous carbon framework with a narrow pore size distribution centered at 3.7 nm. The catalysts were evaluated by the hydrodesulfurization of diben-zothiophene, and the results show that the dibenzothiophene conversion, overall pseudo-first order rate constant and turnover frequency can reach 95 %, 5.4 x 10-6 mol g-1 s-1 and 6.1 x 10-3 s-1 at 300 degrees C, respectively, indicating higher catalytic activity than previously reported catalysts. The higher proportion of the CoMoS active phase can account for the higher catalytic activity. By using in situ-produced sodium chloride crystals and thiourea as hard templates and sulfidizing agents respectively, this study opens a new avenue for the simple and environmentally friendly preparation of hydrodesulfurization catalysts with the synchronization and riveting of MoS2 nanoflakes and 3D mesoporous carbon frameworks. (c) 2022 Elsevier Inc. All rights reserved.